Add httpd(8), an attempt to turn the relayd(8) codebase into a simple

Add httpd(8), an attempt to turn the relayd(8) codebase into a simple
web server.  It is not finished yet and I just started it today, but
the goal is to provide an HTTP server that a) provides minimal
features, b) serves static files, c) provides FastCGI support, and d)
follows common coding practices of OpenBSD.

It will neither support plugins, nor custom memory allocators, EBCDIC
support, PCRE or any other things that can be found elsewhere.
httpd(8) is not intended to provide a fully-featured replacement for
nginx(8) or the Apache, but it will provide enough functionality that
is needed in the OpenBSD base system.

ok deraadt@