Frontent dev env (#247)

* Added frontend development files/environment

* More items-categories related removals

* Improvements in pages templates (inc. static pages)

* Improvements in video player

* Added empty home page message + cta

* Updates in media, playlist and management pages

* Improvements in material icons font loading

* Replaced media & playlists links in frontend dev-env

* frontend package version update

* chnaged frontend dev url port

* static files update

* Changed default position of theme switcher

* enabled frontend docker container

frontend/src/static/js/components/_shared/popup/Popup.jsx

@@ -0,0 +1,29 @@
+import React from 'react';
+
+import './Popup.scss';
+
+const Popup = React.forwardRef((props, ref) => {
+  return void 0 !== props.children ? (
+    <div ref={ref} className={'popup' + (void 0 !== props.className ? ' ' + props.className : '')} style={props.style}>
+      {props.children}
+    </div>
+  ) : null;
+});
+
+export default Popup;
+
+export function PopupTop(props) {
+  return void 0 !== props.children ? (
+    <div className={'popup-top' + (void 0 !== props.className ? ' ' + props.className : '')} style={props.style}>
+      {props.children}
+    </div>
+  ) : null;
+}
+
+export function PopupMain(props) {
+  return void 0 !== props.children ? (
+    <div className={'popup-main' + (void 0 !== props.className ? ' ' + props.className : '')} style={props.style}>
+      {props.children}
+    </div>
+  ) : null;
+}