Add multi routing support.

[monocoder]

Used for specific path prefixes associated with multiple routes. ## For example:

var mainRouter:

...

A sub router can be defined in other files or in the current file. ## There are two sub routes here, users and products, defined in other files.

mainRouter.addRoutesWithPrefix(users, "/api/users") ## mainRouter.addRoutesWithPrefix(products, "/api/products") ## let server = newServer(mainRouter)

server.serve(Port(8080))