Add Twitch prediction support

From Reddit: https://www.reddit.com/r/elgato/comments/lgetjv/prediction_ability_for_stream_deck/?utm_source=share&utm_medium=web2x&context=3

"So as it is right now in order to start a prediction, you have to first type in chat /prediction. Then a new window pops open with a text box asking what you want the prediction to be and two options for people to vote on (customizable of course), then under those boxes is a drop down for how long you want the prediction to last (1m, 2m, 5m, etc.). Finally you click start prediction. My idea would be you could have a single button that could be in the stream deck that already has all the needed information filled out and simply starts the prediction. There would then have to be another 2 buttons programmed to let you pick the outcome winner, but it would be a lot easier than using what twitch has.

For example from a recent stream. Streamer wanted to run a prediction on deku tree ocarina of time, is it a stone or medallion? I had to start the prediction, type out what it was, set the options to stone or medallion, set the time, and then finally run it. Had I not been there, he would have had to stop playing, pause his timer, and type all that out. If I it another mod isn't there, it'd be great to just have. Abutting to press ready to go.

I hope this gives more details

A multi action could be programmed to do it (theoretically), but would be way overcomplicated"

API is now available: https://discuss.dev.twitch.tv/t/announcing-apis-and-eventsub-for-polls-and-predictions/31539

Provide a method for performing OAuth with Twitch
Provide actions for setting predictions and for confirming winner (may need state so other actions still available, ie. set prediction creates new page for results but other pages still available)

SecretAgentKen / deckxstream

Add Twitch prediction support #5