Add include_tables option to DB Sync config

DB Sync currently supports skip_tables to exclude tables from synchronisation.

It would be great to add an include_tables option so users can explicitly define which tables should be synced from the database.

This would be useful when tables are added to a PostgreSQL schema, but only specific ones are intended for MerginMaps sync.

It would also make the sync process safer. At the moment, if new tables are added to the schema, they may automatically become part of the sync process. This can cause unexpected behaviour or potentially break the sync if the new tables are not intended or ready to be synced.

Example:

include_tables:
  - table_1
  - table_4
  - table_9

Start by locating the configuration handling for skip_tables and the sync logic that selects tables from the PostgreSQL schema. Add the documented include_tables option so only the listed tables are synchronized, then verify both explicit inclusion and the existing exclusion behavior with the project's configuration or sync tests.