(TK-20) Webrouting Service

This PR adds a new optional webrouting service that can replace a project's dependency on the Jetty9 webservice. It offers the same functionality as the webservice, but allows the user to specify the endpoints they want specific services to register in their configuration file and add them by passing in the namespaced symbol of a service rather than directly passing in an endpoint.
In terms of the 'let', I agree that will be cleaner.

In regards to the invalid config, I believe that is handled by the WebroutingServiceConfig schema. Since this function is being validated, if `svc-config` doesn't match either of those two schemas it'll violate the WebroutingServiceConfig schema and an exception will be thrown.