Update lighttpd config

The lighttpd config has been split into two files: lighttpd.conf and scgi.conf.
This ensures a separation of concerns: lighttpd.conf is concerned with generic
daemon things like which user to run as, and scgi.conf is concerned with things
like how to contact the SCGI daemon handling ELTS.

lighttpd.conf has also been simplified (unnecessary comments and configs have
been stripped out) and hardened (.git, .svn, .bzr dirs are not served).