Checkpoint commit for OPENDJ-1308 Migrate schema support
Code Review : CR-3230

Align OrderingMatchingRule class on the SDK and replace references to 
this class by reference to MatchingRule interface
 
* Update MatchingRule interface to match SDK equivalent class
** Add comparator() method in 
** Add getGreaterOrEqualAssertion() and getLessOrEqualAssertion() methods
* Implement new methods in AbstractMatchingRule and AbstractOrderingMatchingRule
 classes
* Use Assertions instead of compareValues() method when using an OrderingMatchingRule
* Use comparator when needed 
* Update all classes referencing OrderingMatchingRule class