Allow setting up thumbnail image when sharing link + add open graph title and description
This extends the SEO options added in 1.6.0 (https://yellowgrass.org/issue/conf.researchr.org/896):
Add option to set up theSubmitted by Elmer van Chastelet on 11 February 2019 at 15:20
og:imagemeta property used by Facebook and other social media when sharing a link.
Also, add the
og:descriptionmeta elements to each page next to the meta