* adds new app to project
* adds relation between User model and new APIUserToken model
* adds first implementation for GET of intervention
* adds basic code layout for future extension by having new versions
* adds mail sending if shared data is deleted
* adds/updates translations
* refactors recording mails into separate email template folder email/recording
* moves mail sending to celery worker using shared_task in konova/tasks.py
* adds mail sending for shared access given
* adds UserNotification settings checks for mail sending
* adds/updates translations
