Allow to keep the last mute state for a room widget per user

[MTRNord]

Is your feature request related to a problem? Please describe. When you mute the widget and switch rooms, the mute state isn't kept. This gets annoying sometimes.

Describe the solution you'd like Some way of saving it on a per widget/room base per user.

Describe alternatives you've considered Starting muted by default. But that's against the purpose of a conference.