Add Flake Dev Environment and Optional Package Output

[conneroisu]

TLDR;;
Added a flake.nix and lock file containing pinned dependencies for working on the project.

This pull request introduces Nix-based environment management for the project, including a development shell and build system configuration. The changes focus on setting up a reproducible development environment and defining build and formatting processes using Nix flakes.

Environment setup:

• .envrc: Added support for nix-direnv to automatically load the development environment defined in flake.nix. This includes watching flake.nix and flake.lock for changes and providing feedback if the environment cannot be loaded.

Nix flake configuration:

• flake.nix: Defined a Nix flake with the following features:
  • Development shell: Configured tools and scripts for Go development, including building, running, testing, and linting the project. Tools like golangci-lint, gopls, and cobra-cli are included.
  • Build system: Set up a Go-based build process using buildGo124Module, specifying metadata like project description, homepage, and license.
  • Formatter: Added a formatter configuration (nix fmt) with support for alejandra (Nix files) and gofmt (Go files).