Implementation of Data validation feature in Create a Node API

Added support to validate JSON/XML data without the need of persisting
it in the databse.
 - added "dryRunInQuery" flag as a new query parameter
 - added new method as part of CpsDataService layer to perform data
   validation
 - added new method in yang parser "validateData" to validate
   data without persisting it

Issue-ID: CPS-2361
Change-Id: I43dd33cc6120576d0fac606d5c4b0168d107311d
Signed-off-by: Arpit Singh <as00745003@techmahindra.com>
15 files changed