Add support to detect GitHub actions debug logging

[Sam13]

Encapsulates detection whether GHA debug logging is enabled or not. When enabled (via various mechanisms documented below) the environment variable RUNNER_DEBUG is set to 1.

https://docs.github.com/en/actions/learn-github-actions/variables#default-environment-variables https://docs.github.com/en/actions/monitoring-and-troubleshooting-workflows/enabling-debug-logging

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