Tarbomb

[winny-]

This branch adds a flag to root the tarball/zip so it won't extract multiple files into the user's current directory.

It's not quite feature complete yet as the root folder name isn't meaningful to the user:

$ tar -tzf ~/Downloads/jhmod-v0.0.1-pre3-linux-386.tar.gz 
build-artifacts-1676379384/LICENSE
build-artifacts-1676379384/README.md
build-artifacts-1676379384/examples/
build-artifacts-1676379384/examples/pathlist.txt
build-artifacts-1676379384/jhmod
build-artifacts-1676379384/scripts/
build-artifacts-1676379384/scripts/get-core

It also fixes up the shell scripts to be a bit more idiomatic and pass the shellcheck linter. Also added it as a github action because it'll catch problems otherwise missed.

[wangyoucao577]

Use BINARY_NAME as the folder name seems workable by default. Alternativesly one more artifacts_folder var gives more flexability. Which one do you like?

[winny-]

I think an additional artifacts_folder var might be more clear when authoring workflows.