Add an option to set more configuration for Swagger UI

[abompard]

I need to change the curl options displayed in the Swagger documentation. For that, Swagger has a curlOptions parameter that can be set using the requestInterceptor function. Unfortunately, there doesn't seem to be a way to add this option in Swagger's configuration in the swagger-ui.html template.

I'd love to have either a flask setting or an extension parameter to set such a function. It may also be a good idea to be able to insert any Swagger configuration in the template, but that's more generic that what I need.

I hope it's clear, if not please ask me. Thanks!

[peter-doggart]

@abompard To get around the lack of customization, I just render a custom template (that flask-restx fully supports) and then you can pass whatever configurations you like to Swagger UI during the bundle creation.

See https://github.com/python-restx/flask-restx/issues/430#issuecomment-1104052909