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/pelicanconf.py b/pelicanconf.py
index f7e0f58..d100903 100644
--- a/pelicanconf.py
+++ b/pelicanconf.py
@@ -75,6 +75,7 @@
 PLUGINS = [
     'assets',
     'photos',
+    'videos',
 ]
 
 # Derive categories from the folder name
@@ -207,7 +208,7 @@
 # {url} placeholder in PAGINATION_PATTERNS.
 DAY_ARCHIVE_URL = ''
 
-# Gallery plugin
+# Photos plugin
 PHOTO_LIBRARY = os.getenv('PELICAN_PHOTO_LIBRARY')
 PHOTO_EXCLUDE = os.getenv('PELICAN_PHOTO_EXCLUDE')
 PHOTO_EXCLUDEALL = os.getenv('PELICAN_PHOTO_EXCLUDEALL')
@@ -215,3 +216,10 @@
 PHOTO_ARTICLE = (2000, 1333, 100)
 PHOTO_THUMB = (300, 200, 100)
 PHOTO_SQUARE_THUMB = False
+
+# Videos plugin
+VIDEO_LIBRARY = os.getenv('PELICAN_VIDEO_LIBRARY')
+VIDEO_EXCLUDE = os.getenv('PELICAN_VIDEO_EXCLUDE')
+VIDEO_EXCLUDEALL = os.getenv('PELICAN_VIDEO_EXCLUDEALL')
+VIDEO_GALLERY = (720, 400, 100)
+VIDEO_ARTICLE = (720, 400, 100)