Allow browsing and filtering all relationships instead of just
followers, unify the codebase with the user-facing relationship
manager, add ability to see who the user invited

* Fix unused role routes being generated

* Remove unused JavaScript code

* Refactor filters code to be DRYer

* Fix `.count == 0` comparisons to `.empty?` in views

* Fix filters in views

Rename "abandoned" to "moved", and "active" to "primary"