Improvement: cancel Dauerabmeldung for one session only

@kronlulp idea I'll wait until i have the real database ready I dont want to force another temporal json file to get edited weekly XD

If it were to be with a json file:

• Button handler (Abmeldung/Online/Verspätet)
  • Is dauerabgemeldet
    1. Write userID from member with Dauerabmeldung into specific json file
    2. Delete role from member
    3. (Give Online/Verspätet)
  • is not dauerabgemeldet (Abmeldung)
    1. Check if members userID is written in the specific json file
    2. Delete userID from json file if it is there
    3. Give back dauerabgemeldet
    4. (Remove Online/Verspätet)
• On Scheduled Reminder
  1. Check json file for userID
  2. Delete userID from json file if it is there
  3. Give members with that userID their Dauerabmeldung role back