[DO NOT MERGE] Fixes #6703 - Nest v2 api parameters in Katello

This is a work in progress. I probably wouldn't review it yet.

## API Tasks
- [ ] Update the apidoc (in progress)
- [ ] Figure out what to do about `find_` methods (see https://github.com/Katello/katello/pull/4454)
- [ ] Update tests
- [ ] Test out the API
   - [ ] Test out PUT/POST requests
   - [ ] Test out responses for wrapping (per https://github.com/theforeman/foreman/pull/1605)
- [ ] Update/test hammer
- [ ] Notify QE (robotello)