Provide input parameter to set any SwaggerUI Configuration Parameter

[neumantm]

I think it would be useful to be able to set arbitrary Swagger UI Configuration Parameters via the plugin.

E.g. a config option extra_swagger_ui_options.

[neumantm]

Would this generally be something that you would be willing to add?

If yes, I could look into creating a PR.

[neumantm]

I think this would also solve #30.