Preview of social media (links) in form

Problem/Motivation

When creating or editing a social media paragraph you have no information what the embed would look like or what post the link is referencing. While creating this might be mitigated by the fact that you just copied the link from the platform, but also here you do not get an error if you missed some characters in the URL. However for editing that later you cannot tell from the URL alone what that would look like.

Proposed resolution

Add a "live" embed of the related social media post into the form. That can be done with most of the APIs by using their oembed endpoint that is open without authentication. For more support this could also be optionally enhanced by using a service like Iframely.
What needs to be determined is if this can be a patch for media_entity_instagram and the like or if this is better put in a module that provides a new widget for the link field.

Remaining tasks

1. Create wireframes to show how that would be used in a form
2. Create a design for the backend theme thunder_admin
3. Implement a proof of concept in code
4. See if this can be a patch for the relevant media_entity submodules or needs to be implemented separately