Returns just the global configuration, this allows the config service to be
used independently of objects if desired (all config is placed in a global section).
ConfigSource that looks for a prefix to determine where to look for the config.
Valid prefixes are:
file: the location provided is a path to a physical file
classpath: the location provided is a resource on the classpath
http: the location provided is a HTTP address
jar: the location provided is within a JAR file.