This PR was squashed before being merged into the 7.3 branch.Discussion----------[Cache] Add `\Relay\Cluster` support| Q             | A| ------------- | ---| Branch?       | 7.3| Bug fix?      | no| New feature?  | yes| Deprecations? | no| Issues        | n/a| License       | MITThis PR allows usage of the `\Relay\Cluster` class in `RedisAdapter` when [relay](https://relay.so/) extension is installed in version >= 0.10.0.## Example usage### Creating a connection with authNote that `\Relay\Cluster` will only be used if `relay` extension is loaded```phpuse Symfony\Component\Cache\Adapter\RedisAdapter;$relayCluster = RedisAdapter::createConnection(    'redis:?host[valkey-cluster:6372]&host[valkey-cluster:6373]&host[valkey-cluster:6374]&auth=my-password&redis_cluster=1');$cacheUsingRelayCluster = new RedisAdapter($relayCluster);```### Creating tls connection with self-signed certificate for testing in local environment```phpuse Symfony\Component\Cache\Adapter\RedisAdapter;$relayCluster = RedisAdapter::createConnection(    'rediss:?host[valkey-cluster:6372]&host[valkey-cluster:6373]&host[valkey-cluster:6374]&redis_cluster=1&relay_cluster_context[stream][verify_peer]=false&relay_cluster_context[stream][verify_peer_name]=false&relay_cluster_context[stream][allow_self_signed]=true&relay_cluster_context[stream][local_cert]=/valkey.crt&relay_cluster_context[stream][local_pk]=/valkey.key&relay_cluster_context[stream][cafile]=/valkey.crt&relay_cluster_context[max-retries]=5&relay_cluster_context[client-tracking]=false');```### Alternatively if you already have an instance of `\Relay\Cluster` which you want to use:```phpuse Relay\Cluster;use Symfony\Component\Cache\Adapter\RedisAdapter;$relayCluster = new Cluster(    'my-relay-cluster-client',    [        'valkey-cluster-untracked:6372',        'valkey-cluster-untracked:6373',        'valkey-cluster-untracked:6374',    ],);$cacheUsingRelayCluster = new RedisAdapter($relayCluster);```With this PR, two connection options have been introduced: - ~~`relay_cluster` which is a boolean indicating whether the user wants to create a `\Relay\Cluster` connection~~ Removed in favor of using `redis_cluster` and the fact that `relay` extension is loaded to choose the `\Relay\Cluster` class - `command_timeout` which is consumed by `\Relay\Cluster` and defaults to `0` - `relay_cluster_context` which is consumed by `\Relay\Cluster` and allows user to configure options described incachewerk/relay#161 (comment)CC: `@tillkruss`Commits-------f4a76e0 [Cache] Add `\Relay\Cluster` support

This PR was merged into the 7.3 branch.Discussion----------[Cache] Code cleanup| Q             | A| ------------- | ---| Branch?       | 7.3| Bug fix?      | no| New feature?  | no| Deprecations? | no| Issues        | -| License       | MITFollows#59857 /cc `@dorrogeray` (some changes for the upcoming doc)Commits-------922f5ff [Cache] Code cleanup