Add a sample /etc/sysconfig/httpd file for the dispatcher

While it is good that the documentation references the need to put server-specific configurations into the `/etc/sysconfig/httpd` file, there is no sample provided with all configurable variables.

It would be great if such a file existed, that contained all configurable vars (docroots, hostnames, etc) that could be used to easily create a dispatcher in a local environment, without trawling through every file looking for `${ ... }` and extracting the names.

Read the documentation that references /etc/sysconfig/httpd, then search the project for `${ ... }` variables used by the dispatcher configuration. Done means a sample /etc/sysconfig/httpd file documents all configurable variables, including docroots and hostnames, and can be used to create a local dispatcher.

Written by the indexing model from the issue text.