Updated builders to use GitHub Actions

[qstokkink]

Fixes #97

This PR:

• Updates the build process to run on GitHub Actions.

[egbertbouman]

If I remember correctly, pystray will first attempt to use AppIndicator3 and if that fails it will try AyatanaAppIndicator3.
You could try installing gir1.2-appindicator3-0.1 as well.

[qstokkink]

Alright, Windows also seems to work🎉 Sort of: double clicking a torrent file does not download it. I think that's a separate issue though.

[qstokkink]

I'm not seeing any errors on Mac. I'll have to check on a VM or something whether everything is O.K. there.

[qstokkink]

validate

[qstokkink]

@egbertbouman I still want to switch pull_request to workflow_dispatch but other than that, I'm done. Could you give this a review?

[egbertbouman]

Looks good to me.

Do you still want Jenkins as a fallback? It's still needed for signing the Mac build, so we can't get rid of it entirely.

[qstokkink]

Thanks, I'll turn this into workflow_dispatch and get this merged.

Long term, I'd like* everything to be on GitHub Actions, including signing:

• Windows signing should be reasonably easy with our setup by just using GitHub secrets.
• Mac could be a two-step process. First we could hook our machine in as a "self-hosted runner" into GitHub before using a GitHub-secrets approach. I'm not sure if it is smarter to just do a one-shot port though.

I don't think you can transfer secrets between repos, so I think it would be better to wait until highlander makes its way into Tribler/Tribler.

*I believe GitHub Actions and Jenkins do mostly the same thing so I'd like to keep only one to lessen our maintenance load.

[qstokkink]

validate