Don't allow external admins to set themselves anywhere in the meeting

[luisa-beerboom]

See OpenSlides/openslides-backend#3206

• Remove external admins without meeting membership from any participant selection list.
• Since motion.create doesn't auto-create a submitter from the caller anymore, fill him in in the client create view, if he is in the meeting. Take note that the submitter fields name in the payload has changed to submitter_meeting_user_ids, and now only allows meeting_user_ids.
• External admins who aren't meeting members can no longer create chat messages
• External admins who aren't meeting members can no longer personal notes (the latter includes setting a favourite in the motions). not visible if not part of meeting already, the faviourite icon is now hidden