[mirotalksfu] - add Document PIP

public/views/Room.html

@@ -192,6 +192,7 @@ access to use this app.
             <button id="pollButton" class="hidden"><i class="fas fa-square-poll-horizontal"></i></button>
             <button id="editorButton" class="hidden"><i class="fas fa-pen-to-square"></i></button>
             <button id="whiteboardButton" class="hidden"><i class="fas fa-chalkboard-teacher"></i></button>
+            <button id="documentPiPButton" class="hidden"><i class="fas fa-images"></i></button>
             <button id="snapshotRoomButton" class="hidden"><i class="fas fas fa-camera-retro"></i></button>
             <button id="settingsButton" class="hidden"><i class="fas fa-cogs"></i></button>
             <button id="restartICEButton" class="hidden"><i class="fas fa-satellite-dish"></i></button>