Use Spring's Environment and PropertySource feature to inject configuration

Spring 3.1 introduced the Spring Environment, which provides a flexible way
to add additional property sources. This patch updates UniversalSpringCell
to inject our configuration into the context as property sources. This allows
us to get rid of dCache specific boilerplate in our Spring XML files.

Target: trunk
Require-notes: no
Require-book: no
Acked-by: Albert Rossi <arossi@fnal.gov>
Patch: http://rb.dcache.org/r/6536/