Support for nested/complex types

[chgl]

Something like:

[GenerateFhirParameters]
public class OuterModel
{
    public string Id { get; init; }
    public InnerModel Person{ get; init; } 
}

public class InnerModel
{
    public string Name { get; init; }
    public int Age { get; init; }
}

should be serializable as well. This will probably require repesenting the inner model using part:

{
  "resourceType": "Parameters",
  "parameter": [
    {
      "name": "id",
      "valueString": "OuterModel.Id"
    },
    {
      "name": "person",
      "part": [
        {
          "name": "name",
          "valueString": "InnerModel.Name"
        },
        {
          "name": "age",
          "valueInteger": "InnerModel.Age"
        }
      ]
    }
  ]
}