Add JGenerator::serialize without check a schema

:Release Notes:
Add another JGenerator::serialize without schema verification.
It allows to serialize JValue of any type eg. string, int, array, etc.

:Detailed Notes:
Current version of JGenerator::serialize provides json serialization with
schema verification. As a result simple json values, like string, int,
bool, can not be serialized due to the fact that there is no schema to
validate such json values. The new function will allow to serialize
JValue of any type.

:Testing Performed:
New unit test was implemented

:QA Notes:

:Issues Addressed:
[GF-8543] Provide one more JGenerator::serialize without schema verification

Open-webOS-DCO-1.0-Signed-off-by: Alekseyev Oleksandr <alekseyev.oleksandr@lge.com>

Change-Id: Ib27f353d88c2471e122c7fe4858bb6ca8531ae6d
Reviewed-on: https://g2g.palm.com/2811
Reviewed-by: Build Verification
Reviewed-by: Anatolii Sakhnik <anatolii.sakhnik@lge.com>
Reviewed-by: Alekseyev Oleksandr <alekseyev.oleksandr@lge.com>
Tested-by: Alekseyev Oleksandr <alekseyev.oleksandr@lge.com>