Allow re-arrangement of sub tabs via extension service

[rgallettonf]

Some of the tab's and sub tab's are not properly grouped/associated.

Ie:

• Service Policies, Router Policies, and Service Router Policies should be grouped under "Policies"
• Cert Authorities, JWT Signers, and Auth Policies should be grouped under authentication

Also, as a user extending the entity pages through the shared library, I'd like to be able define my own sub-tab navigation via the extension service(s).