Adds binary build GitHub Action for x86_64-unknown-linux-gnu target

[kobyhallx]

Related issue(s)

#225 Releases don't contain binaries anymore

Resolves (link to issue)

#225 Releases don't contain binaries anymore - resolves partially as it provides Linux Intel only, others to follow.

Description

As a Developer, I would like to have access to the pre-build binary release
so that I could download system appropriate executables and start working with Noir Language.

Summary of changes

.github/workflows/publish-x86_64-unknown-linux-gnu.yml - where the base of GitHub Action is defined
.github/build-nix - where shell script is defined to compile releasable binary along with std_lib contents
nix/mixed.nix - nix definition to fix the linux build environment

Dependency additions / changes

N/A

Test additions / changes

N/A

Checklist

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt with default settings.
• I have linked this PR to the issue(s) that it resolves.
• I have reviewed the changes on GitHub, line by line.
• I have ensured all changes are covered in the description.

Additional context

N/A

[jfecher]

LGTM 👍