Restructure Alliance Auth package (#867)

* Refactor allianceauth into its own package

* Add setup

* Add missing default_app_config declarations

* Fix timerboard namespacing

* Remove obsolete future imports

* Remove py2 mock support

* Remove six

* Add experimental 3.7 support and multiple Dj versions

* Remove python_2_unicode_compatible

* Add navhelper as local package

* Update requirements

allianceauth/authentication/templates/public/lang_select.html

@@ -0,0 +1,15 @@
+{% load i18n %}
+<div class="dropdown">
+    <form action="{% url 'set_language' %}" method="post">
+        {% csrf_token %}
+        <input name="next" type="hidden" value="{{ request.get_full_path|slice:'3:' }}" />
+        <select onchange="this.form.submit()" class="form-control" id="lang_select" name="language">
+            {% get_language_info_list for LANGUAGES as languages %}
+            {% for language in languages %}
+                <option value="{{ language.code }}"{% if language.code == LANGUAGE_CODE %} selected="selected"{% endif %}>
+                    {{ language.name_local }} ({{ language.code }})
+                </option>
+            {% endfor %}
+        </select>
+    </form>
+</div>