refactored StandardRolesBasicTestCase to use all management interfaces

Hi Brian,

this is (probably) one of the last pull requests to standalone tests (I've got one more related to JMX). Mostly, it contains a small but important refactoring of `StandardRolesBasicTestCase` to use all management interfaces, so that we test RBAC not only over native mgmt interface, but also over HTTP, CLI and JMX.

To make that happen, we changed `StandardRolesBasicTestCase` to an abstract class. It has all the tests, and the subclasses provide a specific implementation of `ManagementInterface`. And `ManagementInterface` itself is a small abstraction we created.

On top of that, there is one other small test for runtime reconfiguration of role mapping.

Thanks!

LT