Add a sample for describing a multipart/form-data endpoint for file uploads

[trevonmckay]

I'm not sure what the bodyType would be for an endpoint that accepts multipart/form-data using the OpenApiRequestBodyAttribute.

[justinyoo]

It's not currently supported yet, but it will be implemented.

[justinyoo]

Related to aliencube/AzureFunctions.Extensions#111 and aliencube/AzureFunctions.Extensions#71

[agravity-philipp]

Any update on this? I would really need it :)

[klaudiaknafel]

Are there any updates on when it will be implemented?

[ParimalPa]

We are in need of this - when would this be available?