[FEATURE REQUEST] Missing functionality to represent user scalars as swagger types

[mannol]

I often use two scalars, Email and URL to represent, well, Email's and URL's in input as well as output types. When I use SOFA with openapi/swagger integration, these scalars show up as objects rather than their actual type, which is string. This is a very specific use case so I think SOFA should have an option for users to provide scalar <-> type name mapping when creating an openapi instance.

I'm thinking of contributing this myself, let me know what you think.

[ardatan]

@mannol That sounds great! Feel free to submit a PR and we will support you.