Open graph support feature suggestion

[bastdan]

The open graph meta tags allow better presentation when sharing a web page on social media. Also, adding this meta tags will improve SEO optimization of the page.

The basic meta tags are:

• og:title -> the title of the page, or the content itself, e.g.:
  <meta property="og:title" content="The Rock" />

• og:url -> canonical url of this page, e.g.:
  <meta property="og:url" content="http://www.imdb.com/title/tt0117500/" />

• og:image -> url of an image of 1:1 or 1.91:1 aspect radio, ranging from 600x315 to 1200x1200. This image file will be shown as a thumbnail when sharing the page on social media, e.g:
  <meta property="og:image" content="http://ia.media-imdb.com/images/rock.jpg" />

• og:type -> a list of possible types is available at http://ogp.me/#types. A first version of the implementation could limit this value to 'website' and 'article', e.g:

<meta property="og:type" content="article" />
<meta property="article:published_time" content="2018-04-19T19:56:45+00:00" /> <!-- date time in ISO 8601 format -->
<meta property="article:modified_time" content="2018-04-19T19:56:45+00:00" /> <!-- date time in ISO 8601 format -->
<meta property="article:section" content="Technology" />  <!-- we could assume upper level channel of this content -->
<meta property="article:tag" content="technology,3d printing,etc" />  <!-- a list of tags for this article -->

<meta property="og:type" content="website" /> <!-- Home page and non article pages could have only this type tag -->

Open graph validation could be made here: https://developers.facebook.com/tools/debug/