JSON schema - tailing double quotes for maximum (#6452)
* Fix C/C++ Create<Type>Direct with sorted vectors
If a struct has a key the vector has to be sorted. To sort the vector
you can't use "const".
* Changes due to code review
* Improve code readability
* Add generate of JSON schema to string to lib
* option indent_step is supported
* Remove unused variables
* Fix break in test
* Fix style to be consistent with rest of the code
* Fix double quotes for (u)int8 in json schema
* Fix reference file for JSON schema test
* Fix reference file for JSON schema test