[Feature] Support `activitypub` platform

[nykma]

Not a bounty for now. Just for a record.

• Identity:
  • username@activity_pub.server.com : Not sure if username is really immutable on target server (at least mastodon is indeed immutable)
  • userid_in_database@activity_pub.server.com : Not sure if this field is exposed on target server
• How to fetch public "toot":
  • API : maybe we need many APIKey for each target server
  • Headless browser + view web version of "toot" : maybe OK

[nykma]

Misskey:

• Request: POST /api/notes/show with body {"noteId: "xxxxx"}
• Response: .text

Mastodon, Pleroma:

• Request: GET /api/v1/statuses/{PostID}
• Response: .content

[nykma]

Get node info: GET /.well-known/nodeinfo -> .links[0].href -> GET xxx -> .software.name

[nykma]

https://docs.gotosocial.org/en/latest/api/swagger/

[nykma]

gotosocial hasn't been supported yet.