Conflict with "json_?" and other libraries

[Jhonson Ozuna Mejia]

Bug or Problem:

I was trying to add a JSON library and it name conflicts with flecs functions to work with JSON.

multiple definition of `json_number';  ..ThirdParty/flecs/flecs.c.obj:flecs.c:(.text+0x52eb1): first defined here
multiple definition of `json_string';  ..ThirdParty/flecs/flecs.c.obj:flecs.c:(.text+0x52eb1): first defined here

I propose changing these functions to "ecs_json_" as suggested by user @randy on discord or "json_flecs_" "jsonf_".

[Sander Mertens]

Fixed!