[reactchannel] — Bot Emojis Support

[lisbonjoker]

Like the title says a way to support the new discord feature of Bot Emojis to use them for reactions.

[PhasecoreX]

The underlying discord.py library doesn't support it yet, and then once it does, Redbot will have to be updated to use that new version as well.

Rapptz/discord.py#9891

Once all of that stuff has happened then I can look into adding that feature.