Run hardenedBSD on GitHub action runners

[Robert]

Hello

Over the past month or so I have been focused on running hardenedBSD on
GitHub action runners. The first (and main) challenge was the lack of
official VM images. This is still an issue, and I am building the images
manually before uploading them as GitHub releases. Not ideal but it
works. More details about the build process can be found at [1].

The action itself is [2].
The README explains how it can be used in your own workflows.
It is limited right now, this is the only supported configuration:

release=16-CURRENT
fs=UFS
arch=AMD64

Help and testing would be appreciated, and improvements should continue,
but a little slower than the first round. I am using the action in my
own projects so I know it's not perfect but it's proven useful as well.
That's why I'm sharing it, and in the hope others might join and help
with this effort.

Best regards,
Robert

[1] https://github.com/0x1eef/hardenedbsd-builder
[2] https://github.com/0x1eef/hardenedbsd-vm