[CXF-5878] Disabling policy engine causes NPE
[CXF-5897]: Relax setter method name restriction for @context injection
[CXF-5897]: Update JUnit test to check relaxed validation
[CXF-5897] Using full class names, avoiding direct refs to 2.0 contexts (to support loading CXF 3.0 into 1.1 envs) in a static map