Convert guice configuration to use commons-configuration internally (still uses PropertyFile for loading). This lets us u
se variable interpolation in property files.

Also introduce ConfigurationPropertyRegistry, able to track the @Inject @Named configuration variables across the whole service and expose them to be processed in some manner.
Add basic UI for retrieving configuration properties in use
Add @Doc annotations for @Inject @Named config values for the stdlib core; not all config is accessed this way so it's not as comprehensive as it should be, but it's a step up from nothing
Improve UI for config, include info on binding sites