[REQ] OpenAPI shall handle multiple content types pro operation

Is your feature request related to a problem? Please describe.

Some of our company internal swagger files use multiple content types pro operation. It is allowed by REST-API and currently in use. But OpenAPI generator handles only the first one, others are ignored.

Describe the solution you'd like

If an operation have multiple content types a matching function call shall be generated pro content type, eg:
myFunction(<parameter list 0>)
myFunction_1(<parameter list 1>)
...

Describe alternatives you've considered

Currently I am using ugly workarounds using manual modification of the swagger file before the generation and further manual modifications of the generated C++ classes after the generation. Time consuming, error prone and really ugly.

Additional context

I develop in C++ with Qt, so I use cpp-qt-client generator. But the problem is language independent.
I have already made an in-house extension and I am going to provide it in form of a pull request.

See some swagger snippits, as an illustration of the problem:

paths:
  /myFunction:
    post:
      operationId: "myFunction"
      requestBody:
        content:
          multipart/form-data:
            schema:
              required:
              - "geoWhatever"
              - "payload"
              type: "object"
              properties:
                geoWhatever:
                  type: "string"
                  format: "binary"
                payload:
                  $ref: "#/components/schemas/myFunctionPayload1"
	       application/json:
            schema:
              required:
              - "payload"
              type: "object"
              properties:
                payload:
                  $ref: "#/components/schemas/myFunctionPayload2" 

Start with the cpp-qt-client generator entry point that processes OpenAPI requestBody content, using the YAML example in the issue as a reproduction. Verify how multiple content types are currently reduced to one, then generate separate operation calls for each content type and confirm the generated client preserves the distinct request schemas.