[#73679980] Refactor selector views

  - Increase consistency between Database picker and Schema picker, both can be children of
    Data Source pickers
[#73679980] User can pick workfile execution schema from any db data source

 - Schema picker now supports and oracle/jdbc (data source with schemas as direct
   children)
 - Schema picker flag showAllDbDataSources determines if picker includes all or
   only gp/pg db data sources