Improved live chat support, rename to ytpriv

• Renamed ytwrk to ytpriv, which I think is more fitting. The old name was a hint at the wrk load testing utility, because folks were abusing this tool as if they ran stress tests.
• Updated live chat scraping to the new youtubei endpoint, which seems to be more reliable.
• Added super chat support.
• Added support for top chat (live chat but filtered for spam).
• Added support for live chat replays.

Refactor and cleanup

• Restructured the repo to adhere to Go best practices
• Removed stale and overly use-specific code
• Updated to latest YouTube API and added regression tests
• Added a preliminary video discovery worker for use with od2/Hive

More to come!

First release

Previous releases weren't tagged, so here's 1.0.

Changes:

• Fixed scraping comment threads with more than one page (#13)
• Fixed minor changes to the YouTube API since Q1 2020
• Added --sort=top/new flag to ytwrk video comments