Add proxy_hide_header directive

[thetechnick]

Fixes #86

#configmap
data:
  proxy-hide-headers: X-My-Header,Strict-Transport-Security

#ingress
annotations:
  nginx.org/proxy-hide-headers: X-My-Header,Strict-Transport-Security

will render:

proxy_hide_header Strict-Transport-Security;
proxy_hide_header X-My-Header;

[pleshakov]

That'be great if you could add the proxy_pass_header directive also, as discussed in #86
Please uncheck changes to the Makefile.

[pleshakov]

If the nginx.org/proxy-hide-headers annotations exists, it's better to overwrite the value provided by the configmap. Such a behavior is consistent with the behaviour of the proxy_hide_header NGINX directive.

[pleshakov]

thx!