Completely integrate wepack in django

* Migrate alpine
* Migrate jquery and jquery-ui
* Migrate shorten
* Add babel for javascript
* Introduce staticfiles django app
* Only bundle -index.js files in static/webpack
* Unify scss and webpack generated files
* Convert scss calls to static
* Add --clear-generated option to collectstatic
* Fix docs warnings

counter/models.py

@@ -330,7 +330,7 @@ class Product(models.Model):
         Returns:
             True if the user can buy this product else False
 
-        Warnings:
+        Warning:
             This performs a db query, thus you can quickly have
             a N+1 queries problem if you call it in a loop.
             Hopefully, you can avoid that if you prefetch the buying_groups :

counter/templates/counter/activity.jinja

@@ -6,7 +6,7 @@
 {% endblock %}
 
 {%- block additional_css -%}
-  <link rel="stylesheet" href="{{ scss('counter/css/activity.scss') }}">
+  <link rel="stylesheet" href="{{ static('counter/css/activity.scss') }}">
 {%- endblock -%}
 
 {% block content %}