Feature/633 new name for json object rendering

### Description
New name for JSON object rendering.
The old name 'attributesFormat' is not good.
New name: 'attributeFormat'.
Old name is still supported.

Interesting point.
If we don't, then it seems that an issue has no functest ...
Perhaps just leave 000_ngsi10_compound_values/convop_attributes_as_json_objects.test untouched, copy it to 633*/*.test and modify attributesFormat to attributeFormat in 100% of the file ... (for this case)