Update install docs for discovery service
Update install docs for discovery service

Update the installation documentation to install the Shibboleth
Embedded Discovery Service (EDS) via RPM. Include notes about
required adjustments to config files.

tcmitchell/geni-portal,tcmitchell/geni-portal,tcmitchell/geni-portal,tcmitchell/geni-portal,tcmitchell/geni-portal