Allow .gif emojis
When adding the pack referenced in #817 (closed) I noticed the .gif emojis aren't available. That's probably expected behaviour since the docs also state that the files should be PNG[1].
However, custom emojis are wildly used on the fediverse, including .gif emojis. It would be nice if Pleroma could support those as well as custom emojis on your own instance.
It's possible that there is a reason why .gif isn't done (like accessibility), but I didn't find an issue about this yet, so I assume it's not something that really has been discussed.
[1] https://docs-develop.pleroma.social/custom_emoji.html#emoji-tags-groups