Add admin panel

[BenDavidAaron]

As a product person

I would like to view and edit the system prompts used by Groknag when constructing threads

So that I can adjust Groknag's behavior without having to write up a ticket and wait a week for @BenDavidAaron to change it

Acceptance criteria:

1. Users have an optional admin status
2. Users with admin status are able to add/edit/disable groknag system prompts
3. Users without admin status are not able to add/edit/disable groknag system prompts