Auto inference standalone/distributed mode from configuration

[sunng87]

What type of enhancement is this?

Configuration

What does the enhancement do?

Currently we require user to configure mode to distributed or standalone on frontend (or datanode). Even if we have metasrv address configured for frontend, it still assumes itself as standalone when this mode set to standalone. However, no other feature is affected except the cluster_info meta table reports wrong role.

The suggested solution is to remove this mode configuration item and auto inference its mode based on metasrv configuration.

Implementation challenges

No response