Caching of Reference Codes [#4 responsible:none state:fixed]

Added a new Singleton EJB to act as a cache for reference codes
and settings in the Services Layer. Cached reference values are
automatically flushed/reloaded when the code is updated using
SOLA Admin. SOLA Admin also provides a Flush Cache menu option
(see Reference data menu) to clear all cached values from the
Service Layer so the Administrator can flush the cache if they
update config data directly in the database. The cache is also
scheduled to flush automatically on a daily basis (at 5am local time)