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/packages/player/.modernizrrc

@@ -0,0 +1,8 @@
+{
+  "minify": true,
+  "options": [],
+  "feature-detects": [
+    "css/transforms",
+    "test/storage/localstorage"
+  ]
+}