83377964 reallocate action officer

Need to finish feature spec

* Added gem so thrown exceptions are debuggable in the page
* Make lists default to no bullet style (so they can be used anywhere instead of BRs)
* use correct naming convention for join table association (`action_officers_pqs`) although this should be renamed to assignments (as it has started to be called in places)
* CSV export doesn't require blanks for values (nil works fine). Made logic much cleaner
* Replaced accept/reject flags in join table with a response state (awaiting, accepted, rejected) and added appropriate helper methods. State machine was considered but the responses are too simple for it to add anything
* Added proper associations for directorate and division
* Simplified PQ `rejected?` method
* `reassign` method added to PQ to see new accepted action officer and associated directorate and division
* Fixed a bug in question service (if there are no questions you get an exception due to it expecting a collection but getting an empty string)
* fixed some spacing issues (due to conversion to slim)
* moved action officer selection into a partial