* Ported groups service to user new api v3 and ported dependent controllers
* Remove and extra remove inviation code. Fixed group service caching and update group service tests
* Fixed test logic and added party cache support
* Added promise rejections and updated http interceptor
After some discussion on the thread, this is probably the neatest
solution to issue #6758. I have also modified the code on the guild
controller, which displayed the very same problem when pressing the
'Leave' button to leave a guild.