- update logic of verifying incoming pod's anti-affinity
- rename podMatchesAffinityTermProperties to podMatchesAllAffinityTermProperties
- add podMatchesAnyAffinityTermProperties which is used in some PodAntiAffinity cases
- rename some functions to make it more readable
- add unit tests to verify correctness of PodAffinity and PodAntiAffinity
  - verifying "Existing pod anti-affinity"
  - verifying "incoming pod's anti-affinity"
  - verifying "incoming pod's affinity"