Generate maps without declaring a custom type

[ptodev]

The typical way to generate a map with json schema seems to be:

"properties": {
    "myMap": {
        "type": "object",
        "additionalProperties": {
            "type": "number"
        }
    }
}

However, this generates a custom type:

package test
					
type Map struct {
    MyMap MapMyMap `json:"myMap,omitempty"`
}

type MapMyMap map[string]float64

It'd be cleaner to not have to create a custom type. I cannot think of a reason why we would want a custom one?

I'm also not too sure if we can override the custom map by using the goJSONSchema setting. But not using custom types feels cleaner anyway.

[omissis]

yeah this looks like a nice touch. please fix the qa issues and todos and move the PR in Ready for review so I can review it and merge it. thanks!