Support for in-memory storage

[Tochemey]

No description provided.

[shaj13]

@Tochemey whats this issue for, the title can't describe a feature request please provide the current behavior and what you would like to see

[Tochemey]

@shaj13 This is not an issue. I am just asking whether instead durable raft state, we should also provide an in-memory raft state because there may be some use cases where in-memory state is sufficient without the need of a filesystem