Pods: Make Application Settings to be part of `gitlab_main_clusterwide`

What does this MR do and why?

Part of: #388275 (closed), &9667 (closed).

This introduces gitlab_main_clusterwide as a way to indicate tables that are cluster-wide.

Moves just application_settings and licenses into gitlab_main_clusterwide.

Supplementary to original plan I added licenses since it is tightly connected with application_settings and just works 😄

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.