Deprecate schema name field in table config

Apparently, it's more error-pruning and causing more confusion.

Plan is to always align table name with schema name.

Migration plan:
Controller can scan all tables with customized schema name and copy schema to table name, then update table config. In case the schema name is already occupied. We need to copy schema name to _tmp, all table configs. Iterate all tables, then copy schemas from _tmp to , and update schema name again.

For any new table creation, if there is a reference schema, alway copy the schema then create table without schema name field.

Cc: @Jackie-Jiang

Start at the Controller entry point that scans tables with customized schema names, then trace table configuration and new-table creation. The migration is complete when existing schemas and table configs are aligned without collisions, and new tables no longer use the schema name field.

Written by the indexing model from the issue text.