Introduce a command to restatectl to compact db(s)

[AhmedSoliman]

We need a new cluster admin gRPC API to trigger compactions for one or more of our databases, the API will be exposed through a new sub-command of restatectl.

This API should allow us to run compactions on one or more of the cluster nodes and give us the ability to select which database or all databases to compact.

[david-wagih]

I will work on this one.