OpenGraph metadata for videos

[ludmilamarian]

Add OpenGraph metadata to videos in order to improve Facebook/Twitter sharing (and in general SEO). An example from the current CDS:

<meta content="Title" property="og:title" />
<meta content="website" property="og:type" />
<meta content="https://cds.cern.ch/record/XXXX" property="og:url" />
<meta property="og:video:height" content="YYY" />
<meta property="og:video:width" content="ZZZ" />
<meta property="og:video" content="foo.mp4" />
<meta property="og:video:type" content="video/mp4" />
<meta property="og:image" content="posterframe_X.png" />
<meta name="twitter:player:height" content="XYZ" />
<meta name="twitter:player:width" content="XZY" />
<link rel="image_src" href="thumbnail_X.png" />
<link rel="video_src" href="foo.mp4"/>
<meta name="twitter:player" content="EMBED_URL_FOO"/>
<meta content="CERN Document Server" property="og:site_name" />

(more details: http://ogp.me/)