ci: Add golangci-lint configuration and fix initial linting errors

[ccoVeille]

This pull request lays the groundwork for improving code quality by integrating golangci-lint, a powerful Go linter. Here's what this PR accomplishes:

1. Configuration Setup:

   • Adds the .golangci.yml configuration file.
   • This configuration ensures consistent code style and helps identify potential issues.

2. Initial Code Cleanup:

   • Fixes linting errors detected by golangci-lint in our existing codebase.
   • These corrections address stylistic inconsistencies and minor code smells.

Next Steps (Not Included in This PR):

• CI Integration: The next step is to integrate golangci-lint into our CI pipeline. This will enable automated linting on each pull request.
• Additional Rules: As we gain experience with golangci-lint, we can gradually enable more rules to enhance our code quality further.

Review Checklist:

• Verify that golangci-lint configuration is appropriate for our project.
• All initial linting errors have been adequately addressed.
• Confirm that the changes do not introduce regressions or unexpected behavior.

Fixes #20

[supitsdu]

Seems good to me. Thanks for the contribution. Later I'll have to make a workflow to run the linter. I'll do some research and tests.

See: https://golangci-lint.run/welcome/install/#github-actions
See: https://github.com/golangci/golangci-lint-action

[ccoVeille]

Yes, it can be added very easily.

Have fun with golangci-lint and revive. It's a sane journey