Add a way to customize the `SwaggerUIBundle` parameters

[dzamlo]

SwaggerUIBundle is called in the static/index.html file. Its parameters are hard codded. I would like to set validatorUrl to null. But right now this is not possible.

It would be useful to add a way to customize the arguments to SwaggerUIBundle. Either via a dict of extra arguments or more simply by allowing to pass a string that will be inserted as-is in the html file after the last argument.