Cleanup
Group conversation features update
* Add participant, remove participant
* Get conversation details
* Added new exceptions
* Fix models unsubscription method
* Add subscribe activities for each user at conversation creation
* Change conversation subscription routes to mimic the regular context's ones
* Update tests
Updated docs
* changed hash to id,
* Changed conversation subobject type from message to note
Cleanup: Don't copy __init__ if it's not needed
Cleanup: remove unused function
Fix update
Cleanup: Remove unused lines
Cleanup: remove unused views
Cleanup: remove impossible situation...
Cleanup: Remove unused functions:
Cleanup: Remove impossible situation (2)
Cleanup: Remove unused file
Cleanup: Remove ununsed imports and comment unused code