feat: Add debug log mask support

[f5yacobucci]

NGINX supports multiple debug masks to customize logging.

We use Rust's type system to represent these as an enum and ease a developers usage. They can call the ngx_log_debug_mask with any of the supported enum elements.

To aid in keeping in sync with NGINX primitives a unit test will fail when the current FIRST and LAST log masks do not align any longer.

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• [ X] I have written my commit messages in the Conventional Commits format.
• [ X] I have read the CONTRIBUTING doc
• [ X] I have added tests (when possible) that prove my fix is effective or that my feature works
• [ X] I have checked that all unit tests pass after adding my changes
• [ X] I have updated necessary documentation
• [ X] I have rebased my branch onto master
• [ X] I will ensure my PR is targeting the main branch and pulling from my branch from my own fork

[f5yacobucci]

Believe I have everything addressed. Let me know if you're ok and I'll merge.