Allow for a spec list in SwaggerUIOpts

[rsmarples]

We currently have a gateway service which hosts swagger-ui and it's respective swagger.json
This works fine.
What we want is a means of having a list of spec files to load in the top explore bar.

This seems possible as what I need is documented here: https://swagger.io/docs/open-source-tools/swagger-ui/usage/configuration/

Is there currently a way of doing this?