Add the ability to provide extra http headers through a configuration file, so we can more easily add support for things like CSP. Users can then also add their own headers without needing to modify the code.
Done in r18000. We ship a directory called browser/xpra/trunk/src/http-headers, all files found in this directory are parsed and added to the http headers. The old "nocache" headers are now handled this way, and there is a basic CSP file too.
Noted and closing.
See also HSTS: #1664
this ticket has been moved to: https://github.com/Xpra-org/xpra/issues/1741