fix(uba,ubcli,ub): MT environments - system users

All changes in this MR are related to correct functioning of multi-tenant environments. All the changes are made in a way to preserve behavior for regular environments "as is" to minimize impact/risks/

The following changes are made:

• ubcli, when generates RLS for PostgreSQL (basic underlying mechanism of multi-tenant mode) now support 2 new policies:
  • tenantAndSpecialUsers - to be used by uba_user
  • tenantAndCommonAndSpecialUsers - to be used by uba_subject
• uba_user now has validation rules that disallow update operation on root and anonymous in user tenants
• uba_common module now in the isSuperUser function, in user tenants check is done against user name, not user ID for "admin" user
• Session.runAsAdmin function now for user tenants, redirects to Session.runAsUser with ID of the admin user in that tenant