Move DialogContainer to BaseApp to have dialogs on the welcome screen too

react/features/base/app/components/BaseApp.js

@@ -127,6 +127,7 @@ export default class BaseApp extends Component<*, State> {
                             { this._createMainElement(component) }
                             <SoundCollection />
                             { this._createExtraElement() }
+                            { this._renderDialogContainer() }
                         </Fragment>
                     </Provider>
                 </I18nextProvider>
@@ -235,4 +236,11 @@ export default class BaseApp extends Component<*, State> {
             this.setState({ route }, resolve);
         });
     }
+
+    /**
+     * Renders the platform specific dialog container.
+     *
+     * @returns {React$Element}
+     */
+    _renderDialogContainer: () => React$Element<*>
 }