feat: add support for Discord-style emojis (Twemoji)

[deansheather]

Adds support for Twemoji emojis in the chat window and web interface. The Twemoji emoji set is the same emoji set used by Discord.

To accomplish this, the entire set of Twemoji is checked into the repo (hence the massive change count), as well as a JSON document that converts emoji shortcodes to their corresponding unicode. The updating of these files is handled by a Powershell script that can be run whenever things need to be updated.

hello :wave: im cryin rn :sob::sob::sob:

Future improvements that can be made:

• Currently the twemoji support is controlled by the existing "Show emotes" toggle, maybe it could be split into it's own setting
• Twemoji emotes cannot be blocked via the "Blocked emotes" setting
• There's no autocomplete support for Twemoji like Discord has
• There's no way to set default skin-tone for emojis, you need to know the full emoji code if you want to send a non-default skin-tone

But it's a good foundation I think.