Support for custom Permissions Policy HTTP header in Nginx

[jessuppi]

Support for custom Permissions Policy HTTP header in Nginx

[jessuppi]

Since we are using a unique Nginx server blocks directory /var/www/sites/ we probably should ensure that any custom child config files are in a subdirectory there to avoid confusion.

For example like:

/var/www/sites/custom/

[jessuppi]

I was going back on forth on this but I don't think custom is a good sudirectory name. It sounds like maybe users could replace default server blocks with their own but that's not true, it's just for Nginx includes only.

So I'm proceeding with calling this /var/www/sites/includes/

91ac5a6

After a few Google searches it looks like Roots Trellis uses a similar folder name nginx-includes so that's good, at least some similar naming helps the community.

Ref: https://roots.io/trellis/docs/nginx-includes/

Still pending integration with SlickStack installer scripts and the main Nginx config file...

[jessuppi]

See here:

## pending testing ##
# include /var/www/sites/includes/featurepolicy.conf;

For better security/control perhaps we can include specific child includes only as they become approved by the community instead of just a wildcard include...

https://github.com/littlebizzy/slickstack/blob/master/modules/nginx/nginx-conf.txt

[jessuppi]

https://forum.nginx.org/read.php?11,256135

Hi, you may use the include directive with some glob() pattern tricks

For instance, replace this

include /path/to/something/nonexisting.conf

with

include /path/to/something/nonexisting[.]conf

the config parser won't complain if such file does not exist.

Not sure if still relevant.