Offer room creation form

A choice of public or private is offered, which maps to matrix'
visibility parameter. A name can also be provided.

Change-Id: I34d99acbc4624a9ed54ca6f6609573d5fc1049da

src/App.js

@@ -4,7 +4,7 @@ import polyglotI18nProvider from "ra-i18n-polyglot";
 import authProvider from "./synapse/authProvider";
 import dataProvider from "./synapse/dataProvider";
 import { UserList, UserCreate, UserEdit } from "./components/users";
-import { RoomList } from "./components/rooms";
+import { RoomList, RoomCreate } from "./components/rooms";
 import LoginPage from "./components/LoginPage";
 import UserIcon from "@material-ui/icons/Group";
 import { ViewListIcon as RoomIcon } from "@material-ui/icons/ViewList";
@@ -40,7 +40,11 @@ const App = () => (
       edit={UserEdit}
       icon={UserIcon}
     />
-    <Resource name="rooms" list={RoomList} icon={RoomIcon} />
+    <Resource
+      name="rooms"
+      list={RoomList}
+      create={RoomCreate}
+      icon={RoomIcon} />
     <Resource name="connections" />
   </Admin>
 );