Add new user's status in muc light

[DemonH]

Hello, could you add new users status in muc light conference like read-only. Not block or other things. New status can be read and can't be written. It will look like channel in telegram or other applications.

[fen-pl]

Hi @DemonH

Thanks for the suggestion. I'm afraid it's not a trivial change to MUC Light logic but I'll make a note of this in our backlog and we'll see when we can take care of it.