## Description- I consolidated all commits from#1107 into this new PR.- The previous storage-clients implementation was completely replacedwith a redesigned clients, including:    - new storage-client interface,    - in-memory storage client,    - file-system storage client,- Apify storage client (implemented in the SDK; seeapify/apify-sdk-python#470),    - and various adjustments elsewhere in the codebase.- The old "memory plus persist" client has been split into separatememory and file-system implementations.- The `Configuration.persist_storage` and`Configuration.persist_metadata` options were removed.- All old collection clients have been removed, they're no longerneeded.- Each storage client now prints warnings if you pass method argumentsit does not support.- The creation management modules in the storage clients and storageswere removed.- Storage client parameters (e.g. `purge_on_start`, or `token` and`base_api_url` for the Apify client) are configured via the`Configuration`.- Every storage, and its corresponding client, now provides both a`purge` method (which clears all items but preserves the storage andmetadata) and a `drop` method (which removes the entire storage,metadata included).- All unused types, models, and helper utilities have been removed.- The detailed, per-storage/client changes are listed below...### Dataset- Properties:    - `id`    - `name`    - `metadata`- Methods:    - `open`    - `purge` (new method)    - `drop`    - `push_data`    - `get_data`    - `iterate_items`    - `list_items` (new method)    - `export_to`- Breaking changes:- `from_storage_object` method has been removed - Use the `open` methodwith `name` or `id` instead.    - `get_info` -> `metadata` property    - `storage_object` -> `metadata` property- `set_metadata` method has been removed (it wasn't propage to clients)        - Do we want to support it (e.g. for renaming)?- `write_to_json` -> method has been removed, use `export_to` instead    - `write_to_csv` -> method has been removed, use `export_to` instead```pythonimport asynciofrom crawlee.storage_clients import FileSystemStorageClientfrom crawlee.storages import Datasetasync def main() -> None:    dataset = await Dataset.open(storage_client=FileSystemStorageClient())    print(f'default dataset - ID: {dataset.id}, name: {dataset.name}')    await dataset.push_data({'name': 'John'})    await dataset.push_data({'name': 'John', 'age': 20})    await dataset.push_data({})    dataset_with_name = await Dataset.open(        name='my_dataset',        storage_client=FileSystemStorageClient(),    )    print(f'named dataset - ID: {dataset_with_name.id}, name: {dataset_with_name.name}')    await dataset_with_name.push_data([{'age': 30}, {'age': 25}])    print('Default dataset items:')    async for item in dataset.iterate_items(skip_empty=True):        print(item)    print('Named dataset items:')    async for item in dataset_with_name.iterate_items():        print(item)    items = await dataset.get_data()    print(items)    dataset_by_id = await Dataset.open(id=dataset_with_name.id)    print(f'dataset by ID - ID: {dataset_by_id.id}, name: {dataset_by_id.name}')if __name__ == '__main__':    asyncio.run(main())```### Key-value store- Properties:    - `id`    - `name`    - `metadata`- Methods:    - `open`    - `purge` (new method)    - `drop`    - `get_value`    - `set_value`- `delete_value` (new method, Apify platform's set_value support settingan empty value to a key, so having a separate method for deleting isuseful)    - `iterate_keys`    - `list_keys` (new method)    - `get_public_url`    - `get_auto_saved_value`    - `persist_autosaved_values`- Breaking changes:- `from_storage_object` method has been removed - Use the `open` methodwith `name` or `id` instead.    - `get_info` -> `metadata` property    - `storage_object` -> `metadata` property- `set_metadata` method has been removed (it wasn't propage to clients)        - Do we want to support it (e.g. for renaming)?```pythonimport asyncioimport requestsfrom crawlee.storage_clients import FileSystemStorageClientfrom crawlee.storages import KeyValueStoreasync def main() -> None:    print('Opening key-value store "my_kvs"...')    storage_client = FileSystemStorageClient()    kvs = await KeyValueStore.open(name='my_kvs', storage_client=storage_client)    print('Setting value to "file.json"...')    await kvs.set_value('file.json', {'key': 'value'})    print('Setting value to "file.jpg"...')    response = requests.get('https://avatars.githubusercontent.com/u/25082181')    await kvs.set_value('file.jpg', response.content)    print('Iterating over keys:')    async for key in kvs.iterate_keys():        print(f'Key: {key}')    print('Listing keys:')    keys = [key.key for key in await kvs.list_keys()]    print(f'Keys: {keys}')    for key in keys:        print(f'Getting value of {key}...')        value = await kvs.get_value(key)        print(f'Value: {str(value)[:100]}')    print('Deleting value of "file.json"...')    await kvs.delete_value('file.json')    kvs_default = await KeyValueStore.open(storage_client=storage_client)    special_key = 'key with spaces/and/slashes!@#$%^&*()'    test_value = 'Special key value'    await kvs_default.set_value(key=special_key, value=test_value)    record = await kvs_default.get_value(key=special_key)    assert record is not None    assert record == test_value    result = await kvs_default.list_keys()    print(f'kvs_default list keys = {result}')    kvs_2 = await KeyValueStore.open()    result = await kvs_2.list_keys()    print(f'kvs_2 list keys = {result}')if __name__ == '__main__':    asyncio.run(main())```### Request queue- Properties:    - `id`    - `name`    - `metadata`- Methods:    - `open`    - `purge` (new method)    - `drop`    - `add_request`    - `add_requests_batched` -> `add_requests`    - `fetch_next_request`    - `get_request`    - `mark_request_as_handled`    - `reclaim_request`    - `is_empty`    - `is_finished`- Breaking changes:- `from_storage_object` method has been removed - Use the `open` methodwith `name` or `id` instead.    - `get_info` -> `metadata` property    - `storage_object` -> `metadata` property- `set_metadata` method has been removed (it wasn't propage to clients)        - Do we want to support it (e.g. for renaming)?- `get_handled_count` method had been removed - Use`metadata.handled_request_count` instead.- `get_total_count` method has been removed - Use`metadata.total_request_count` instead.- `resource_directory` from the `RequestQueueMetadata` was removed, use`path_to...` property instead.- `RequestQueueHead` model has been removed - Use`RequestQueueHeadWithLocks` instead.- Notes:- New RQ `add_requests` contain `forefront` arg (Apify API supports it)```pythonimport asynciofrom crawlee import Requestfrom crawlee.configuration import Configurationfrom crawlee.storage_clients import FileSystemStorageClientfrom crawlee.storages import RequestQueueasync def main() -> None:    rq = await RequestQueue.open(        name='my-queue',        storage_client=FileSystemStorageClient(),        configuration=Configuration(purge_on_start=True),    )    print(f'RequestQueue: {rq}')    print(f'RequestQueue client: {rq._client}')    await rq.add_requests(        requests=[            Request.from_url('https://example.com', use_extended_unique_key=True),            Request.from_url('https://crawlee.dev', use_extended_unique_key=True),            Request.from_url('https://apify.com', use_extended_unique_key=True),        ],    )    print('Requests were added to the queue')    is_empty = await rq.is_empty()    is_finished = await rq.is_finished()    print(f'Is empty: {is_empty}')    print(f'Is finished: {is_finished}')    request = await rq.fetch_next_request()    print(f'Fetched request: {request}')    await rq.add_request('https://facebook.com', forefront=True)    request = await rq.fetch_next_request()    print(f'Fetched request: {request}')    rq_default = await RequestQueue.open(        storage_client=FileSystemStorageClient(),        configuration=Configuration(purge_on_start=True),    )    await rq_default.add_request('https://example.com/1')    await rq_default.add_requests(        [            'https://example.com/priority-1',            'https://example.com/priority-2',            'https://example.com/priority-3',        ]    )    await rq_default.add_request('https://example.com/2')if __name__ == '__main__':    asyncio.run(main())```### BaseDatasetClient- Properties:    - `metadata`- Methods:    - `open`    - `purge`    - `drop`    - `push_data`    - `get_data`    - `iterate_items`### BaseKeyValueStoreClient- Properties:    - `metadata`- Methods:    - `open`    - `purge`    - `drop`    - `get_value`    - `set_value`    - `delete_value`    - `iterate_keys`    - `get_public_url`### BaseRequestQueueClient- Properties:    - `metadata`- Methods:    - `open`    - `purge`    - `drop`- `add_requests_batch` -> `add_batch_of_requests` (one backend methodfor 2 frontend methods)    - `get_request`    - `fetch_next_request`    - `mark_request_as_handled`    - `reclaim_request`    - `is_empty`- Models    - `RequestQueueHeadWithLocks` -> `RequestQueueHead`    - `BatchRequestsOperationResponse` -> `AddRequestsResponse`- Notes:- Old file system (memory) version didn't persist the in-progressrequests- Old file system (memory) version didn't persist the forefront values(now there is a FS-specific `_sequence` field in the FS Request)- The methods manipulating locks and listing heads are now only internalmethods of Apify RQ client.## Issues-Closes:#92-Closes:#147-Closes:#783-Closes:#1247- Relates:#1175- Relates:#1191## Testing- The original tests were mostly removed and replaced with a new ones.- Each storage-client implementation now has its own dedicated tests atthe client level (more targeted/edge-case coverage).- On top of that, there are storage-level tests that use a parametrizedfixture for each storage client (`file-system` and `memory`), ensuringevery storage test runs against every client implementation.## Checklist- [x] CI passed