`[roles-0.1.0]` Describe hats models, load a full hats tree

[adamgall]

• [x] Create some classes / models / interfaces / whatever in the codebase to hold hats roles / wearer data.
  • [x] Keep it simple and minimal to start, with just a couple of the most important properties per object (prob just: name / relationships / wearers)
  • [x] Make this data populate into state upon regular Safe page load
• [x] Create the data fetching code / structures necessary to, given a Safe address (probably the Safe address right?), load up hats roles for the tree that this Safe is in (right? are there some more assumptions we can be making here)
• [x] Don't need any UI yet, just log out the data

[adamgall]

Completed via https://github.com/decentdao/decent-interface/pull/2028