Implement Acegi Security

From OpenNMS

The milestone provides a more robust security infrastructure for OpenNMS and removes the requirement for the Tomcat specific security realm and, therefore, dependence on Tomcat itself. This will allow the OpenNMS Web Application to be deployed to any Web Application container. Acegi pretty much requires the Spring Framework IOC container but only as a configuration (dependency injection) mechanism. Acegi can use AspectJ for method interception and doesn't use any Spring specific interfaces.

This milestone will allow make use of a more advanced security model resticting access to objects in the domain as well as features/functionality in the service layer. With this new security model, portal technology can be made available.