BUG 484 Anyxml normalized node

- DataNormalizationOperation: added AnyXmlNormalization for
  AnyXmlSchemaNode

- Moved DataNormalizerTest to sal-common-impl where the source code
  resides and added more tests including coverage for anyxml.

Originally commited under patch set 9
https://git.opendaylight.org/gerrit/#/c/7337/9 by Tom Pantelis

This commit depends (therefore is commited as draft) on commits:
- Add Anyxml normalized node to yang-data-api -
https://git.opendaylight.org/gerrit/#/c/7771/1
- Implementation of Anyxml builder -
  https://git.opendaylight.org/gerrit/#/c/8061/

Change-Id: I8f6febd1738cde3139cc32d8199d1a87c464ba34
Signed-off-by: Jozef Gloncak <jgloncak@cisco.com>