Support alternative types of instant messengers (e.g. Matrix)
Currently it seems only XMPP is supported, but I use Matrix instead. I tried just entering an alias, but it seems it's ignored and wiped on save.
It would be good to allow more types of instant messengers here. Maybe add some preset ones (XMPP, Matrix, IRC), and allow a "custom" option where the user can give their own name for a service.