feat(Assignments)

[marcelklehr]

Todo:

• Refactored ChattyLLMController to factor out business logic into a service
• Implemented Assignments backend logic (db, APIController, Service, BgJob)
• Implemented RRule checking
• Implement front-end
  • Small header for assignment sessions to indicate what's going on
  • Maybe disable the chat input for assignment sessions?
  • Maybe a small icon for the chat session overview for assignment sessions
  • Query the session list regularly and for assignment sessions we need to check for new generations regularly
• Implement better session titles for assignment sessions