Configuration for disallowing certain emotes

[BenDMyers]

Some streamers may not want to display certain emotes, especially if those emotes are against their channel or team's code of conduct or which might not be suitable for their demographic.

The first line of defense for most of these streamers should probably be adding those emotes' names to their channel's banned words list, but in the case that doing so would come off as too forceful, we should offer a second line of defense to ensure that a channel's disallowed emotes don't show up as their emote forms in their chat overlays.

Suggested API

We should support a disallowedEmotes query parameter for overlays that would take a comma-separated list of emote names and ensure that those emotes don't get rendered. For example, /c/BenDMyers?disallowedEmotes=somean3CoolTuna,somean3Howdy would prevent the somean3CoolTuna and somean3Howdy emotes from showing as their emote forms.

We could even support a disallowedEmotes=* option if streamers don't want any emotes to show.

What To Do With Disallowed Emotes

What does it mean to not render an emote? The way I see it, we have two options:

1. Where the emote was meant to be, display nothing. It's as if the sender had never included the emote.
2. Display the emote's name (e.g. display somean3CoolTuna in place of the Cool Tuna emote)

I think option 1 has some hidden complexity to it — for instance, what if the sender's message contains only disallowed emotes? Do we reject the message altogether? I don't think this is unsolvable by any stretch, but it might be simpler to go with option 2.

[BenDMyers]

Another thing to consider: what the interface for this should look like in the homepage's overlay URL builder.