Add devices tab to UserEdit component

Allows to view user devices.
API was added by synapse v1.15.0.

Change-Id: Id0693bf6cd6f6182c657412cf8036537e2db9df7

src/App.js

@@ -37,6 +37,7 @@ const App = () => (
     />
     <Resource name="rooms" list={RoomList} show={RoomShow} icon={RoomIcon} />
     <Resource name="connections" />
+    <Resource name="devices" />
     <Resource name="servernotices" />
   </Admin>
 );