tracking: support native integration with superset via the postgres driver

[neverchanje]

• bug: "Timestamp cmp Varchar" error when comparing timestamp field with "to_timstamp" #7736
• missing typarray in the pg_type table #9939
• Tracking: System Table in pg_catalog #2954 fully support the pg_type system table.
• Tracking: System Table in pg_catalog #2954 fully support the pg_namespace system table

Seems risingwave has been added to superset's official support list, but we didn't utilize it yet.
https://github.com/apache/superset/blob/master/superset/db_engine_specs/risingwave.py

Superset's PostgreSQL driver native support: connection function test completed, platform capability basic test completed, all datatype can be recognized.

[fuyufjh]

Hi, @jetjinser @neverchanje May I close this issue? Seems done

[jetjinser]

I think it's okay to close