Reply to a reply
Add support for replying to a reply, to improve interactions to ActivityPub side of things.
- reply button for each reply, to target the right reply on ActivityPub side. Need to figure out how to do the UI for this without making it confusing looking
- automatically add a mention of the replied reply and the original author to the new reply if replying to a previous reply, otherwise add a mention of the original author
- ensure the ActivityPub inReplyTo value is the replied to reply, not the original post, if replying to a reply
Doing these three would highly improve the possibility to actually talk with users on Mastodon et al.