Project Health (PH) metrics for Shaka Player

See https://joeyparrish.github.io/shaka-player-ph/

The dashboard uses a modified version of freeboard. It also uses a modified version of the freeboard-jqplot plugin to show graphs. Finally, the custom freeboard-ph plugin displays Project Health (PH) metrics as defined by Google.

The raw data that drives all this is collected by Python scripts that live in the ph/ folder. They call the GitHub API through the gh command-line tool, then process the data into JSON files that are consumed by freeboard.

A GitHub Actions workflow updates the metrics and deploys everything to GitHub Pages every morning.

The token used by the workflow requires repo scope to download workflow artifacts.