Show a lobby screen in video rooms (#8287)

* Show a lobby screen in video rooms

* Add connecting state

* Test VideoRoomView

* Test VideoLobby

* Get the local video stream with useAsyncMemo

* Clean up code review nits

* Explicitly state what !important is overriding

* Use spacing variables

* Wait for video channel messaging

* Update join button copy

* Show frame on both the lobby and widget

* Force dark theme for video lobby

* Wait for the widget to be ready

* Make VideoChannelStore constructor private

* Allow video lobby to shrink

* Add invite button to video room header

* Show connected members on lobby screen

* Make avatars in video lobby clickable

* Increase video channel store timeout

* Fix Jitsi Meet getting wedged on startup in Chrome and Safari

* Revert "Fix Jitsi Meet getting wedged on startup in Chrome and Safari"

This reverts commit 9f77b8c227c1a5bffa5d91b0c48bf3bbc44d4cec.

* Disable device buttons while connecting

* Factor RoomFacePile into a separate file

* Fix i18n lint

* Fix switching video channels while connected

* Properly limit number of connected members in face pile

* Fix CSS lint

test/components/views/rooms/RoomHeader-test.tsx

@@ -176,6 +176,7 @@ function render(room: Room, roomContext?: Partial<IRoomState>): ReactWrapper {
                 room={room}
                 inRoom={true}
                 onSearchClick={() => {}}
+                onInviteClick={null}
                 onForgetClick={() => {}}
                 onCallPlaced={(_type) => { }}
                 onAppsClick={() => {}}