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/.babelrc

@@ -0,0 +1,12 @@
+{
+	"presets": [
+		"@babel/react", ["@babel/env", {
+			"modules": false,
+			"useBuiltIns": "usage",
+    		"corejs": 3,
+			"targets": {
+				"browsers": ["defaults"]
+			}
+		}]
+	]
+}