JSON list support when updating multiple datanodes

JSON list support when updating multiple datanodes

updateDataNodesAndDescendants if supplied with a JSON list such as
 {"branch": [{"name":"Name1"}, {"name":"Name2"}]}
would only replace the first node /test-tree/branch[@name='Name1'],
and ignore any remaining list items. This is caused by the use of a
legacy buildDataNode, which returns only a single DataNode from JSON,
even if the JSON contained a list.

Issue-ID: CPS-1889
Signed-off-by: danielhanrahan <daniel.hanrahan@est.tech>
Change-Id: I257491b6bc3f047a64eb241eaac70fd457b24347