add schema for meta-data JSONs

:Release Notes:
Introduced service meta-data description json schema.

:Detailed Notes:
schemas for:
- category
- map of category name to category format
- generic reply (to be referenced by library clients)

:Testing Performed:
jsonlint

:QA Notes:

:Issues Addressed:
[BHV-1587] Design category description format
[BHV-1588] Create JSON schema for category description

Open-webOS-DCO-1.0-Signed-off-by: Nikolay Orliuk <nikolay.orliuk@lge.com>

Change-Id: I4f2dfbd7428315dd035d26eadbefa6dcc89a6b6a
Reviewed-on: https://g2g.palm.com/5003
Reviewed-by: DCO Verification
Reviewed-by: Nikolay Orliuk <nikolay.orliuk@lge.com>
Tested-by: Nikolay Orliuk <nikolay.orliuk@lge.com>
Reviewed-by: Anatolii Sakhnik <anatolii.sakhnik@lge.com>