* Implement membership endpoints

* Use FillBuilder when possible

* Fix typo in membership event content

* Fix state key invite membership events not being correctly set

* Set membership content to match the profile of the user in state_key

* Move event building and rename common function

* Doc getMembershipStateKey

* Check if user is local before lookin up their profile

* Use gomatrixserverlib function to split user ID

* Propagate profile update via m.room.member events

* Send profile data on room join

* Send profile data on room creation

* Rename variable

* Move membership update to roomserver consumer

* Improve iteration

* Move event update from client API server to sync API server

* Change the way buildMembershipEvents is called

* Forbid update of someone else's profile

* Use gomatrixserverlib method

* Fix depth and previous events not being set

* Fix wrong removal in latest commit

* Update all events instead of only memberships

* Handle case where there is no state key

* Fix test

* Profile retrieval

* Saving avatar (without propagating it)

* Saving display name (without propagating it)

* Getters for display name and avatar URL

* Doc'd

* Introduced new Kafka topic and producer

* Updated config with new kafka topic

* Switched to samara producer and now sending messages

* Doc'd

* Put kafka update after the database insert

* Doc'd profileUpdate structure

* Removed unused parameter

* Moved user updates producer to clientapi/producers

* Profile retrieval

* Saving avatar (without propagating it)

* Saving display name (without propagating it)

* Getters for display name and avatar URL

* Doc'd

* Remove unused import

* Applied requested changes

* Added auth on PUT /profile/{userID}/...

* Improved error handling/reporting

* Using utils log reporting

* Removed useless checks