[Action] Tracking the energy consumption of GitHub Actions Pipelines

[all-green-dev]

Pipelines are not only a great tool for automating tedious tasks, they are also probably a mayor energy consumer. Optimizing them could be worthwhile, however their actual energy demand is currently neither visible nor well researched.

Eco-CI is an approach to measure/estimate the energy consumption of a GitHub Actions Pipeline. This could be a great tool to raise awareness and a first step towards optimization.