Fix inheritance links to use correct namespace in PostgreSQL

[professor93]

Summary

• Fixed "Inherits from" and "Inherited by" links showing wrong namespace (always "public")
• Modified inheritsFrom() and inheritedTables() to return namespace with table name
• Updated tables_links() to generate URLs with correct namespace

[vrana]

Thanks, this is really useful. In other places, Adminer highlights links to different schemas in other places so I've added it here too.