Adding activities

[dartcafe]

Recreation of #2138 because of unsolvable merge conflicts

resolves #804

First implementation of activities integration

• Added activities
• Owner can see activities in a poll
• Users see their activities in the activity app
• Avoid spamming using the uniqueUniqueConstraintViolationException of the logs (identical actions are only triggered once, until logger cron is executed)
• logging and other actions are triggered via listeners
• extended event types and listeners

Fixes, enhancements and optimizations in different PRs