Add contact users to personal filtering community

[olmari]

Feature request:

Matrix-community -style user/chatlist (whichever possible) for whatsapp in ones contact list. Basically same thing that mautrix-facebook implements.

[tulir]

Personal filtering communities are already implemented (they were here before mautrix-facebook and mautrix-hangouts), but the difference is that contact users don't get added, only rooms do.

[tulir]

I think contact users are added now too