have table in db that keeps track of when caches should be refreshed

Right now in the DB config we use a config entry that indicates if any config has changed.  this should be in a separate table so we arent having point in time churn when we keep track of dbConfig point in time

This is in config item:

grouper.config.millisSinceLastDbConfigChanged 

This would be a two col table with a label and an integer (millis since 1970).  The label can be used for things to know when something is updated.  The grouper JVM can centrally poll this whole table every so often (min 10 seconds configurable, and as needed) to see when things have changed.

grouper_cache_notification

Col: label varchar(30) PK and index

Col: millis_since_1970_when_changed index