feat: new welcome modal, refactor many things, various bug fixes, use material-ui v5 etc

Co-authored-by: Alex Sparkes <turbomarshmello@gmail.com>

src/components/widgets/Widgets.jsx

@@ -43,6 +43,11 @@ export default class Widgets extends React.PureComponent {
   }
 
   render() {
+    // don't hide when welcome is there
+    if (localStorage.getItem('showWelcome') === 'true') {
+      return <div id='widgets'></div>
+    }
+
     // allow for re-ordering widgets
     let elements = [];