Set body parameters to requestBody field in case if openapi 3 is used

[arcan1s]

According to documentation https://apispec.readthedocs.io/en/latest/api_ext.html#apispec.ext.marshmallow.openapi.OpenAPIConverter.schema2parameters in=body parameter is no longer allowed for parameters list and must be set to requestBody

This MR simply set data to another field based on location parameter, only tests have to be significantly hacked.