plugins: videos: photos: add videos plugin

This change adds a new plugin that mirrors photos functionality, but for
videos (mp4 and others).

NOTE: this plugin requires ffmepg installed on the host machine

  $ sudo apt-get install -y ffmpeg
diff --git a/theme/templates/article.html b/theme/templates/article.html
index 11e32c5..d8bd049 100644
--- a/theme/templates/article.html
+++ b/theme/templates/article.html
@@ -38,6 +38,22 @@
   {% if not DISPLAY_META_ABOVE_ARTICLE %}
     {% include "modules/article_meta.html" %}
   {% endif %}
+  {% if article.video_gallery %}
+  <div class="gallery">
+  {% for title, gallery in article.video_gallery %}
+    <h1>{{ title }}</h1>
+    {% for video, width, height, format in gallery %}
+    <video width="{{ width }}" height="{{ height }}" controls>
+      <source src="{{ SITEURL }}/{{ video }}" type="video/{{ format }}">
+	  Your browser does not support the video tag.
+    </video>
+    {% endfor %}
+  {% endfor %}
+  </div>
+  {% endif %}
+  {% if not DISPLAY_META_ABOVE_ARTICLE %}
+    {% include "modules/article_meta.html" %}
+  {% endif %}
 
   {% if DISQUS_SITENAME %}
   <div id="article_comments">