Misskey: Update poll federation

[acid-chicken]

Summary

From tootsuite/mastodon#10111 and #3940.

Working at poll branch.

[acid-chicken]

Memo: have to support anyOf choices.

[Gargron]

• anyOf (multiple-choice)
• endTime (expiration date) (closed when already expired)
• For each item in oneOf/anyOf, you can add replies: { type: 'Collection', totalItems: 123 } instead of (or additionally to) _misskey_votes

[acid-chicken]

@Gargron Thank you for the useful info!

[Gargron]

@acid-chicken Perhaps you can help me answer these?

https://github.com/tootsuite/mastodon/pull/10111#discussion_r261871048
https://github.com/tootsuite/mastodon/pull/10111#discussion_r261870760

[Gargron]

I have another request... Could you use name to federate poll votes instead of content (or _misskey_content?), so we can avoid HTML and also differentiate between normal replies and votes easier

[acid-chicken]

@Gargron Misskey will start using name property when #4409 is merged!