Fix the build pipeline in GitHub Actions

[mpdude]

This hopefully makes the builds all 🟩 again.

Many changes were necessary to fix the Coding Standards check. See comments below for explanations of particular other changes.

[mpdude]

@Yozhef I know you have a lot of other, more important things to worry about 😢 .

Maybe if you could approve my workflows to run – this might be an easy merge, and would get the builds back to 🟢 .

[mpdude]

Or maybe @pamil you can approve my workflows to run (needs manual approval for first-time contribution).

[Yozhef]

@mpdude I will look at everything tomorrow and write back.

[mpdude]

Thank you @Yozhef!