batch adding of emoji

Would easy enough to enable upload of many at a time, but need a way to enter a label + shortcode for each in the form.

Related issues: https://github.com/bonfire-networks/bonfire-app/issues/908 https://github.com/bonfire-networks/bonfire-app/issues/908

Relevant code:

• Upload of custom emoji: https://github.com/bonfire-networks/bonfire_files/blob/main/lib/web/upload_emoji_live.ex and https://github.com/bonfire-networks/bonfire_files/blob/main/lib%2Fdefinitions%2Femoji_uploader.ex
• inclusion of custom emojis in text: https://github.com/bonfire-networks/bonfire_common/blob/main/lib%2Ftext.ex#L590-L640 and https://github.com/bonfire-networks/emote/blob/master/lib/emote.ex