raft: Improve raft configs validation
This MR adds two validations for Raft configs:
- Validate if Raft's ClusterID is UUID.
- Validate if Transactions (WAL) is enabled.
The later validation is crucial because Raft could not work without WAL.
This MR adds two validations for Raft configs:
The later validation is crucial because Raft could not work without WAL.