Is your feature request related to a problem? Please describe.
The Matrix Media Repo config allows you to specify datastores in readonly mode by leaving forKind array empty. However, this playbook only includes the datastore in the target yaml config file when kind is specified. That means, it is not possible to move from file datastore to s3 (or reverse) afterwards.

Describe the solution you'd like
Always include both datastores, even if they have no kinds specified.

Describe alternatives you've considered
Add another config option to overwrite the general rule to force-include a datastore even if it has no kinds specified.

Additional context
In my case I want to move from file datastore to s3 and keep file as readonly for the existing media. For this to work at the moment I need to keep at least one kind enabled for file datastore. Otherwise it will be removed from the target yaml config file.