www/nginx - Security Headers - add support for Reporting API

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Is your feature request related to a problem? Please describe. I'm playing around with reports from website monitoring and came across URIports guide. I'm trying to add the headers with the nginx-plugin but hey don't seem to be supported yet.

Describe the solution you'd like

Extend the Security Headers by these HTTP response headers:

1. Report-To
2. Reporting-Endpoints
3. NEL (Experimental)

Add directives to CSP:

1. report-to
2. report-uri (deprecated, but still recommended for backwards compatibility)

Additional context https://www.w3.org/TR/reporting-1/