Tune Nix configurations for CI/CD integration

[placek]

As a DevOps engineer,

I want to adapt Nix configurations to be compatible with our CI/CD tools, specifically GitHub Actions,

So that we can create specific CI/CD pipelines that leverage Nix for building, testing, and deploying applications efficiently.

Acceptance Criteria:

• Nix configurations are adapted for compatibility with GitHub Actions workflows.
• CI/CD pipelines leveraging Nix for all phases are developed and operational.
• Pipelines are optimized for performance and reliability, with changes documented.