Fixes integration tests for Basic Roles PEP (Java implementation)

This also include refactoring of test classes in order to make it possible to reapply tests to subsequent PEP implementations that reuse the same roles but perform their enforcement differently. (Such as XACML) It also includes some undergirding test classes that could be used to set up tests of arbitrary roles.

Includes permission checks for remove node actions that cascade to check child permissions.