Include system tables (sys, information_schema, pg_catalog) in AdminUI

Right now the system tables are filtered (sys, information_schema, pg_catalog) in the Admin UI.
People often aren't aware, that tables like `sys.jobs` or `sys.jobs_log` exists. Therefore I would propose to also include those in the AdminUI, as it often is the first touchpoint for new users.

Including those tables includes significant rework, as the tables-view includes calculations for cluster health based on table shards. System tables don't have information in `sys.shards`. Just removing the filters leads to a **red** cluster state in the Admin UI (i.e. there needs to be a logic to differentiate between system tables and user tables)