HPPC-8551 Refactor the serialization functions

- Introduce two serialization functions in the IOutputMetaData
- Rename and rationalise some of the existing functions
- Start work on dictionary serialization functions
- Distinguish between internal and disk serialation formats
- Clean up serialisation code

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
HPCC-8551 Fix additional issues with serialization

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
HPCC-8551 Move tests to regression suite

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
HPCC-8551 Fix some minor issues picked up by code review

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
Merge pull request #3907 from ghalliday/issue8551b

HPPC-8551 Refactor the serialization functions

Reviewed-By: Jake Smith <jake.smith@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>