V2: Complete overhaul / rewrite

[xTVaser]

Primary motivator was to switch to twitch's configuration service, which they did not offer at the time the original extension was made. That meant hosting my own server which is an annoying cost + maintenance burden that frequently has downtime. This meant dealing with the code that was thrown together as fast as possible almost 5 years ago -- a rewrite was much easier way to go. Notable changes besides the lack of a backend:

• actually wrote tests this time
• using a sane framework instead of jquery
• significantly fewer calls to speedrun.com -- though ironically this can perform worse than making hundreds of individual calls due to performance issues on their end.