Add global fullscreen toggle button

app/stylus/components/Room.styl

@@ -232,6 +232,14 @@
 					}
 				}
 
+				&.fullscreen {
+					background-image: url('/resources/images/icon_fullscreen_white.svg');
+
+					&.on {
+						background-image: url('/resources/images/icon_fullscreen_exit_white.svg');
+					}
+				}
+
 				&.screen {
 					&.on {
 						background-image: url('/resources/images/no-share-screen-black.svg');
@@ -250,6 +258,7 @@
 						background-image: url('/resources/images/share-screen-extension.svg');
 					}
 				}
+
 				&.raise-hand {
 					background-image: url('/resources/images/icon-hand-white.svg');