according to the specification the jcr:setAccessControlPolicy and
jcr:getAccessControlPolicy privileges are also used to grant permission for
AccessControlManager.addAccessControlEntry(String, Principal, Privilege)
However, the description of the privileges states, that they are used to get and
modify the AccessControlPolicies.
To me it makes sense to use them for both AccessControlPolicy and -Entry related
methods, but i would in this case rename them to something more general.