feat(toolbar-button-clicked) Enhance toolbar buttons with notify click

- add possibility to allow execution of the button's routine besides triggering
`toolbarButtonClicked` API event
- keep backwards compatibility
- get rid of `ToolbarButton`

react/features/recording/components/LiveStream/AbstractLiveStreamButton.js

@@ -77,13 +77,7 @@ export default class AbstractLiveStreamButton<P: Props> extends AbstractButton<P
      * @returns {void}
      */
     async _handleClick() {
-        const { _isLiveStreamRunning, dispatch, handleClick } = this.props;
-
-        if (handleClick) {
-            handleClick();
-
-            return;
-        }
+        const { _isLiveStreamRunning, dispatch } = this.props;
 
         const dialogShown = await dispatch(maybeShowPremiumFeatureDialog(FEATURES.RECORDING));