SEO support : add support for image settings (for Open Graph)

Open Graph is used by Facebook[1], LinkedIn[2] and Twitter[3] to pull the title, description and image when sharing a url.
Open Graph can be applied in the template of the project that uses the plugin, but the image is not provided yet.
The only change to allow projects to use all of the Open Graph is provide the image.

Can this also be ported to the version for Hippo CMS 11?

[1] https://developers.facebook.com/docs/sharing/webmasters#markup
[2] https://developer.linkedin.com/docs/share-on-linkedin#
[3] https://developer.twitter.com/en/docs/tweets/optimize-with-cards/guides/getting-started