Add visibility indicators to media listings

- Private media now shows [private] in bold
- Unlisted media now shows [unlisted] in bold
- Public media has no indicator (default)

russell@unturf.com is the boss

templates/list_media.html.j2

@@ -10,6 +10,11 @@
         {% for media in media_items %}
             <li>
                 <a href="{{ request.route_url('view_media_details', namespace_short_id=namespace.short_id, media_short_id=media.short_id) }}">{{ media.title or media.filename }}</a>
+                {% if media.visibility == 'private' %}
+                    <strong>[private]</strong>
+                {% elif media.visibility == 'unlisted' %}
+                    <strong>[unlisted]</strong>
+                {% endif %}
                 ({{ media.media_type }}, {{ media.size|filesizeformat }})
             </li>
         {% endfor %}