Option to "Collapse" similar post types by the same user within the same day

[EdwardHinkle]

Based on this conversation https://chat.indieweb.org/dev/2019-05-22#t1558543428288900
There should be a way to combine posts similar to what Wordpress is doing: https://en.blog.wordpress.com/2017/03/21/reader-combined-cards/

My initial thoughts are it should be the same author, within the same day and the same PTD (Like, Repost, Photo, etc).

I don't know that this should happen for regular notes, videos or audio.

I think this makes sense for the following Post Types:

• Articles
• Photos
• Like
• Repost
• Checkins
• Bookmark

The following post types should probably be gathered underneath the post that they are in reply to rather than by author:

• Reply (Under the original post)
• RSVP (Under the event post)

The following post types are highly experimental but makes sense to also collapse when they are supported:

• Jam
• Read
• Watch
• Listen
• Issue