HSEARCH-1447 Adding testcase
HSEARCH-1447 Adding new helper methods to determine whether a given XClass contains Search annotations at all. Adding test case as well
HSEARCH-1447 Fixing implementation of MappingModelMetadataProvider#getAnnotations which was returning the empty array
HSEARCH-1447 Introducing MetadataProvider#containsSearchMetadata(Class<?>) and extracting AnnotationMetadataProvider our of AbstractDocumentBuilder.

Updating tests affected by document builder refactoring
Cleanup: moving test into sub-package impl
Cleanup: trying to improve readability of test