Update install guide

The installation guide pdf that is posted to the modules wiki page
https://wiki.openmrs.org/display/docs/Radiology+Module

in the Resources section, is not up to date with the latest codebase.

We should thus update the guide, might be better to create a child wiki page for this install guide. So we can easily keep it up to date with the latest changes made to
https://github.com/openmrs/openmrs-module-radiologydcm4chee