steal release script from xash3d-fwgs & update ci/cd

[developersu]

Continuous deployment flow in form of 'Pre-releases'.
For your consideration.
Looks like this: https://github.com/developersu/Goldleaf/releases

Pros:

• it's fun
• latest releases for anyone who wants to run latest builds here and now

Cons:

• floods on GH landing page

Requires GITHUB_TOKEN generation & setup. I did it like this:

(yeah, it might be obvious, but it took me some time)