[feat] Intercept the request for creating a dynamic scalarConfig.

[matvp91]

The swagger plugin creates a new Elysia instance under the hood and threats the arguments as static.

const app = new Elysia()
    .use(swagger({
       documentation: { ... }
       scalarConfig: { ... }
    }))

Let's say I have a securitySchemes defined in the documentation. I'd like to change the scalarConfig to include a default bearer token when I pass it as a query param.

documentation: {
  ...
  components: {
    securitySchemes: {
      bearerAuth: {
        type: "http",
        scheme: "bearer",
        bearerFormat: "JWT",
      }
    }
  }
}

scalarConfig: {
  ...
  authentication: {
    preferredSecurityScheme: "bearerAuth",
    http: {
      basic: {},
      bearer: {
        token: query.token
      }
    }
  }
}

This way I could generate documentation with sane defaults for a specific user.

https://localhost:8080/swagger?token=...

I'm open to idea's and happy to provide a PR once we have a clearer path forward.