Clean up code that is publishing to Publishing API

Tidy up some of the code around publishing editions and organisations to content store via the publishing API. Primarily:

* Separate the code for publishing to Publishing API  from the code for registering with Panopticon
* Add additional comments as sign-posting to the temporary nature of the information currently being published
* Make publishing of organisations consistent with editions.
* Rename the sidekiq worker classes to use terminology more appropriate to the publishing API