WIP: updating naming conventions

[f5yacobucci]

Consistently use _ptr and _mut_ptr for our functions that return *mut and *const pointers.

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

[f5yacobucci]

I did not update the Module trait function names, as these match 1:1 with the NGINX names I left them untouched and consistent with the C naming semantics.

[f5yacobucci]

TODO: update README with a conventions section

[dekobon]

@f5yacobucci Is this PR now obsolete?