HPCC-11922 DESDL add JSON Support

Add rewindTo IXmlWriterExt method
Add JSON builder, JSON test
Add JSON helper functions to esp/services/common

Signed-off-by: rpastrana <rodrigo.pastrana@lexisnexis.com>
HPCC-11922 Changes from code review

- IXmlWriterExt.rewindTo() not valid for flusher type
- Move wsexcept from LN/esp/esdllib to esp/services/common
- Move non json specific logic from JsonHelpers to HttpParamHelpers
- Cleared tmp strbuffer upon every appendjsonexceptions iteration
- Moved buildJsonMsg from ws_ecl to JsonHelpers
- ws_ecl now utilizes JsonHelpers

Signed-off-by: rpastrana <rodrigo.pastrana@lexisnexis.com>
HPCC-11922 Changes from code review

- Substitute all static method class for namespace scoping
- Refactor odd member field nomenclature

Signed-off-by: rpastrana <rodrigo.pastrana@lexisnexis.com>
HPCC-11922 More changes from code review

- Refactor member vars

Signed-off-by: rpastrana <rodrigo.pastrana@lexisnexis.com>
HPCC-11922 Changes from code review

IxmlWriter now provides mechanism for outputing numerics via
outputString

Signed-off-by: rpastrana <rodrigo.pastrana@lexisnexis.com>
HPCC-11922 Code review changes

- IXmlWriter outputBool should translate string to bool

Signed-off-by: rpastrana <rodrigo.pastrana@lexisnexis.com>
HPCC-11922 Further code review changes

Move boolean handling out of XmlWriter interface definition,
All callers must implement their own string -> boolean logic.

Signed-off-by: rpastrana <rodrigo.pastrana@lexisnexis.com>
HPCC-11922 Move isnumeric flag out of IxmlWriter methods

Implement new IxmlWriterExt method for numeric represented as strings

Signed-off-by: rpastrana <rodrigo.pastrana@lexisnexis.com>
HPCC-11922 Remove method implementation from interface

Signed-off-by: rpastrana <rodrigo.pastrana@lexisnexis.com>
HPCC-11922 Clean-up

- Remove commented out line and extra blank line
- Change Unimplemented exception for Unexpected
- Correct copyright date

Signed-off-by: rpastrana <rodrigo.pastrana@lexisnexis.com>
Merge pull request #6405 from rpastrana/HPCC-11922-NEW-JSON-Support

HPCC-11922 new json support

Reviewed-By: Anthony Fishbeck <anthony.fishbeck@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>