Fix ability to do authorization assertions against entities

AclAuthorizationFactory had not been properly updated to look for the "entity"
key in a set of service authorizations; it was still checking against
"resource". Added a unit test for the factory, and a fix for the behavior.

See https://groups.google.com/a/zend.com/d/msgid/apigility-users/b7723f69-e4cc-4619-84d8-c3dd8c1f93a5%40zend.com
Merge branch 'hotfix/authorization-entity'

Fixes authorization against entities.