Migrate testing infrastructure to GH Actions

[labkode]

trafficstars

Today we rely on a on-premise DroneCI platform that CERN needs to maintain, the goal is to migrate to GH Actions.

[phil-davis]

Note for reference: https://docs.github.com/en/billing/managing-billing-for-github-actions/about-billing-for-github-actions https://github.com/orgs/community/discussions/26054

It seems that GitHub Actions are free-unlimited for public repos. So it should be possible to run the existing sets of tests as GitHub Actions.

https://docs.github.com/en/actions/learn-github-actions/usage-limits-billing-and-administration

Each job (pipeline) can run for a maximum of 6 hours - that is more than we need or want for a single job!

Up to 20 concurrent jobs are scheduled for free public repos. That should also be enough to put the various test suites into separate pipelines, similar to what is done now, and have a set of about 20 pipelines that run for a PR.

[labkode]

@phil-davis thanks for the summary, we're also thinking on hosting a GH runner here to speed up the tests if needed. GH actions provide much more integrations nowadays than Drone.