The UserStore and PropertyUserStore classes are hard to re-use for caching eg JDBC data

[janbartel]

9.4.x

The o.e.j.security.UserStore and o.e.j.security.PopertyUserStore classes are hard to re-use. The intention is to provide an L1 cache of user authentication and authorization information, with the various XXXLoginService classes providing the interface to the persistent store. However, the way the classes are currently written, they are only used by the HashLoginService class. Some of the behaviour of the PropertyUserStore could usefully be incorporated into the UserStore to provide a cache that can periodically be emptied/replenished from the XXXLoginService classes.