The current network namespace parameter nested in the JailerConfigparameter requires specifying the entire jailer configuration, which is notconvenient and doesn't allow using the noop jailer with a networknamespace.To overcome this limitation, add a new NetNS parameter to the CreateVMrequest.See also a similar change infirecracker-microvm/firecracker-go-sdk#155.Signed-off-by: Georgiy Lebedev <lebedev.gk@phystech.edu>

In order to support firecracker snapshot-restore we need to make thefollowing changes:* add a new CreateSnapshot request;* add new parameters for snapshot loading to the CreateVM request(following the firecracker Golang SDK design, snapshot loading isessentially creating a VM with additional snapshot options).When a VM is created by loading a snapshot, it's container snapshot drivesare already mounted, so the drive mount stub creation and mounting isskipped.Also add a NetNS (network namespace) parameter to the CreateVM request,since the current NetNS parameter nested in the JailerConfig parameterrequires specifying the entire jailer configuration, which is notconvenient.Signed-off-by: Georgiy Lebedev <lebedev.gk@phystech.edu>