v4: Room member invite (mail)
An implementation for grantRoomRoleByInvitation is needed. There are a few design decisions to be made:
- Do we keep the old behavior? It was inconvenient because users had to verify although this would not be necessary because they indirectly did so by using the invitation link.
- Would it make sense to create a (temporary) unverified account for the invited user, which is then immediately added as a member?
- Are there any other options?