Updating dox for mod_rest. Ideas expressed / clarified: 1) Making clear that mod_rest isn't to be installed under VirtualHosts AND as a component. 2) Understanding some of the implications of this choice: A) Changes to user authentication B) How it affects subdomains 3) More consistent use of domain names for clarity. 4) Using different heading sizes to show scope of section. Essentially, I added all the tidbits I had to clarify in getting this to work in my own example.

Introduction
============

This module creates stub configuration files for newly activated hosts.

Configuration
=============

A single option exists, `persisthosts_path`, which is the path where new
stub configuration files are created. It defaults to `"conf.d"`, and is
treated as relative to the configuration directiory [^1] unless set to
an absolute path.

[^1]: usually `/etc/prosody` on \*nix systems