Ability to request and add new chapters

This PR covers the ability to request new chapters (#2) as well as basic approval and rejection of the options.

- Request new Chapter page now includes list of Chapter Requests
- If the user is an admin user then they can also accept/reject the requests
  - On accept the chapter is created and original requester added as a user
  - On reject the request gets deleted
- Admin user is determined by a system variable `TRY_THINGS_ADMIN_USERNAME`
- `withNewDatabase` and `withSeededDatabase` moved to its own trait

## Thoughts

- Want to think about the tolerance around outright rejection of requests etc.  - seems a tad aggressive.
- Probably want to refactor the chapter request stuff out of the `Chapter` controller into it's own one - it's big enough