Switch to using GH Actions

[jrfnl]

As Travis for open source has died a quiet dead, I propose switching the CI building over to GH Actions.
While we're at it, we may as well get rid of Ant as well.

I have made preparations to action this. and PR #13 and #14 are preliminary PRs before pulling the PR to switch the CI over.

[jrfnl]

PR #16 is another prelim PR. Once that has been merged, I can pull the GH Actions PR.

[grogy]

PR #16 merged ;)

[jrfnl]

And the CI switch over PR has now been pulled ;-)

[grogy]

You are fast! Give me a moment.. :-))

[grogy]

Thank you, it looks very good :))

[jrfnl]

You are fast! Give me a moment.. :-))

grin Well, I had the commits ready locally, all I needed to do was rebase & run a final test with it. (see the commit date)