OPENDJ-1368 (CR-3177) Remove AttributeValue
Removing calls to Entry.getAttributeValue() and Entry.getAttributeValues() that indirectly calls AttributeValue.getNormalizedValue().
Replaced them with calls to new method Entry.parseAttribute(), added to match the SDK API.
AttributeParser.java: ADDED
Added for Entry to match the SDK API.
AttributeValueDecoder.java: REMOVED
Superseded by Attributeparser.
*Syntax.java:
Removed all subclasses of AttributeValueDecoder.
SubtreeSpecificationSet.java: REMOVED
Now unused.