OR-561 Refactor join|leave buttons
OR-571 Propagate communities membership changes into pubsub for join

* Publish in local and global pubsub when join is called
* Fix webserver controllers and middleware with core change
* Fix and add some unit tests
OR-571 Propagate communities membership changes into pubsub for leave

* Publish in local and global pubsub when leave is called
* Fix webserver controllers and middleware with core change
* Fix and add some unit tests
OR-571 Add events documentation
OR-574 Add the wsserver files for community events

* Propagate the community:join and community:leave event to websocket
* Add tests
OR-561 fix indentation
Merge pull request #374 in OR/rse from ~RPIGNOLET/rse:OR-571 to master

* commit '013241ca3a466d07f0db7725430b85e5915ea858':
  OR-571 Add events documentation
  OR-571 Propagate communities membership changes into pubsub for leave
  OR-571 Propagate communities membership changes into pubsub for join
Merge pull request #375 in OR/rse from ~RPIGNOLET/rse:OR-574 to master

* commit '5e5a16bb397fff10839bcf2ef9f03cf0d3d06e36':
  OR-574 Add the wsserver files for community events
Merge pull request #380 in OR/rse from ~MBAILLY/rse:OR-561-integration-ticket to master

* commit '907cf65807a129c216dcce1250a021e88c9678d8':
  OR-561 fix indentation
  OR-561 Refactor join|leave buttons