Fixes for Reverse Proxy Go-Live (#6)

* Add new area for defining upstream systems.

* Example file for demonstration domain.

* Use the new upstream hosts section.

* Do the proxy directives in the main file.

* Commit any final changes.

* Fix example resource name.

* Mention the need to have ports specified in the upstream file, not server block.

* Adjust formatting.

Config/ReverseProxy/config/hosts/README.md

@@ -0,0 +1,3 @@
+# Upstream Host Configuration
+For systems which do not resolve well such as ignoring `/etc/hosts`.
+