Build RLS isolation for a single table

As a POC we want to try RLS based Organization isolation on a simple low traffic table.

This should be as minimal risk as possible. Maybe a table only used on gitlab.com? The RLS policy should also be disabled at runtime if needed - likely through application_name controls.

There are some code examples in:

• &17809
• https://docs.google.com/document/d/1xBcuZeaELLsqyQKPFmKAxKYO5iLIe_aSl-S7qBxoZS4/edit?tab=t.3fjmeh1kb64m