Add API to get all actual rules that apply to an entity (inherited ones)

The API to getActualRules() is part of the description of the needs / expectations in RIGHTSAPI-1 but was not implemented in version 1.
This task it about implementing this function.

Contrary to its current javadoc, the getActualRules() should not return the implied rights by default (or it should be possible to fetch the actual rules without the implied ones with a parameter).