pv_headers: Add remove all headers function

[fprdkhti]

Pre-Submission Checklist

• [x] Commit message has the format required by CONTRIBUTING guide
• [x] Commits are split per component (core, individual modules, libs, utils, ...)
• [x] Each component has a single commit (if not, squash them into one commit)
• [x] No commits to README files for modules (changes must be done to docbook files in doc/ subfolder, the README file is autogenerated)

Type Of Change

• [ ] Small bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds new functionality)
• [ ] Breaking change (fix or feature that would change existing functionality)

Checklist:

• [ ] PR should be backported to stable branches
• [ ] Tested changes locally
• [ ] Related to issue #XXXX (replace XXXX with an open issue number)

Description

This function removes all the headers. it is useful when calling it and setting skip_headers modparam. pvh_apply_headers() function remove all the headers except those specified in the skip_headers .

[miconda]

Shouldn't the function be better named pvh_remove_all_headers instead of pvh_remove_all_header?

@linuxmaniac: any other comments on this PR?

[fprdkhti]

Shouldn't the function be better named pvh_remove_all_headers instead of pvh_remove_all_header?

@linuxmaniac: any other comments on this PR? Yes. I fixed it. Thanks.

[miconda]

@linuxmaniac: is this ok to merge?

[linuxmaniac]

@fprdkhti please document this new feature on https://github.com/kamailio/kamailio-wiki at docs/features/new-in-devel.md