Add 7TV emotes to nodecg-io-twitch-addons

[devJimmyboy]

Added 7TV Emotes to the providers in nodecg-io-twitch-addons

Sadly, since Javascript variables (and object properties) can't start with numbers, I made 7tv's property on EmoteCollection 'stv' so users can access the collection with emotes.stv instead of using a string key with access through emotes["7tv"]

var emotes = await client.getEmoteCollection... // Get emotes
// Easier to access:
emotes.stv.find(v => v.name === "docSpin")
// An annoyance to access:
emotes["7tv"].find(v => v.name === "docSpin")

Since it's common to make 7TV optional (at least in the chat clients I've looked over), I also modified the second parameter of getEmoteCollection (previously a boolean for 'includeGlobal') to be more of an "options" parameter. It's now an object of type:
{ includeGlobal: boolean, include7tv: boolean } and has default values of { includeGlobal: true, include7tv: false } so users can just call getEmoteCollection(emotes) without the options.

If I missed anything in my PR then please let me know!

Heres my NodeCG console printing a test of the providers' emote lengths (the '7tv' key is just part of the test object):

Cheers!
devJimmyboy

[hlxid]

Thank you very much