UX improvements

* ignore English articles when sorting names
  * added a new sort_name field that gets automatically created
* automatically fill certain values in forms:
  * new game: name and sort name after typing
  * new edition: name and sort name when selecting game
  * new purchase: platform when selecting edition

games/templates/add_edition.html

@@ -1,22 +0,0 @@
-{% extends "base.html" %}
-
-{% block title %}{{ title }}{% endblock title %}
-
-{% block content %}
-    <form method="post" enctype="multipart/form-data">
-        <table class="mx-auto">
-        {% csrf_token %}
-
-        {{ form.as_table }}
-        <tr>
-            <td></td>
-            <td><input type="submit" value="Submit"/></td>
-        </tr>
-        </table>
-    </form>
-{% endblock content %}
-
-{% block scripts %}
-{% load static %}
-<script type="module" src="{% static 'js/add_edition.js' %}"></script>
-{% endblock scripts %}