WEBP, APNG & Support More Image Hosting Platforms

[alexankitty]

Just a few features I'd like to see added.

1. Better gif support. Make it possible to query the gif platform (giphy and tenor) to grab the actual gif.
2. webp support. All discord emojis get converted to webp support, and this would be a nice stop gap combined with discordsrv set to show on emotes to be able to view them in game.
3. apng support. All animated stickers are apng format, supporting this would allow them to be viewable in game. It is worth noting that normal stickers do display just fine.

[LOOHP]

It would be nice to support more animated images that work in the Discord client. I've added support for tenor gifs in the recent commit. More will come in the future slowly but surely.