CI based on GitHub Actions

[Johnsel]

This PR implements a basic CI setup on GitHub Actions. The CI produces a zipped artifact that gets attached to a tag only when a commit is tagged with a version. I also fixed the references in the project and workspace files to no longer refer to folders outside of the project root. This is bad practice as it would require the CI to manage files outside of it's project root folder. If one would prefer to develop this way on a local machine a symlink should allow you to, while retaining the CI system integrity. I also included a snippet that relates to NuGet publishing, if you want to template from it.

[issus]

I intend to implement this pull request, but first I'll get AltiumSharp/BxlSharp/EagleSharp into NuGet to improve the build process