public static org.apache.commons.configuration.Configuration getConfiguration()
Get a Configuration interface that combines all resources
found under all of the org.dataone.configuration/config.xml
files from all application packages.
In the case of property key collision, those from configurations
loaded first override those loaded later. So, recommend creating
keys with a package-specific prefix to avoid unnecessary
System properties are always loaded first, followed by those
properties in an optional file (specified with the system
property "opt.overriding.properties.filename"), followed by
context-specific default properties files.
an aggregate Configuration for all properties loaded