Feature request: Manual participant selection

implement a configuration parameter to make “single/manual participant selecion”
0 = no manual/single selection
10 = no selection mode by default
20 = manual/single selection by default
21 = Same as 20 + discard all other streams
30 = manual/single selection only
31 = Same as 30 + discard all other streams

This is to make a participant sees and listens only one other participant, until manually selects another one.

This could open the possibility to more than one speaker people are talking at same time, or some participants are videos playing. Save bandwidth too.