Convert subscription manager to flask framework

youtube/templates/unsubscribe_verify.html

@@ -0,0 +1,19 @@
+{% set page_title = 'Unsubscribe?' %}
+{% extends "base.html" %}
+
+{% block main %}
+    <span>Are you sure you want to unsubscribe from these channels?</span>
+    <form class="subscriptions-import-form" action="/youtube.com/subscription_manager" method="POST">
+        {% for channel_id, channel_name in unsubscribe_list %}
+            <input type="hidden" name="channel_ids" value="{{ channel_id }}">
+        {% endfor %}
+
+        <input type="hidden" name="action" value="unsubscribe">
+        <input type="submit" value="Yes, unsubscribe">
+    </form>
+    <ul>
+        {% for channel_id, channel_name in unsubscribe_list %}
+            <li><a href="{{ '/https://www.youtube.com/channel/' + channel_id }}" title="{{ channel_name }}">{{ channel_name }}</a></li>
+        {% endfor %}
+    </ul>
+{% endblock main %}