Add import of Audioscrobbler files

Here we add a model for holding Audioscrobbler imports and some code to
process the tab-separated files we get from Rockbox.

vrobbler/templates/scrobbles/upload_form.html

@@ -0,0 +1,13 @@
+{% extends "base.html" %}
+{% block content %}
+<main class="col-md-4 ms-sm-auto col-lg-10 px-md-4">
+    <div class="d-flex justify-content-between flex-wrap flex-md-nowrap align-items-center pt-3 pb-2 mb-3 border-bottom">
+        <h1 class="h2">Manual scrobble</h1>
+        <form action="{% url 'audioscrobbler-file-upload' %}" method="post">
+            {% csrf_token %}
+            {{ form }}
+            <input type="submit" value="Submit">
+        </form>
+    </div>
+</main>
+{% endblock %}