Feature request: Ability to add new top-level category for regions

[varunratnakar]

Is your feature request related to a problem? Please describe.
As MINT is adapted to newer areas like wildfire, the regions aren't always restricted to Administrative, Hydrology and Agriculture. Modifying this requires changing the code to add new icons, and changing the backend to add a new top-level category.

Describe the solution you'd like
A "Plus" sign somewhere on the main regions page that asks for an Icon and Name, and creates the category in the backend