Feature Request for Open Graph meta embed tags

[delcake]

Currently when linking posts from a Ktistec instance to a service that displays rich link preview embeds (Discord, Facebook, etc.), no preview is generated due to a lack of OG/Twitter meta properties. Details on the Open Graph protocol are available at https://ogp.me/

If possible, I think dynamically generating these tags for each post would be a great addition to allow for a presentable ~160 character preview of the content when linking to it on services that support them. Depending on how you want to structure the previews, it might be a reasonable default to always display the poster's avatar as the image preview and Display Name (@username@domain) as the title.