Move routes to urls package

To lock down V2 api routing, we are moving it to a separate package, with an
exported router creation function and route names. Updates will follow to
prepare the package for export.
Prepare urls package for exports

The route definition files have been prepared for export with documentation.
Consts have been updated and tests are now passing for the urls package.
Porting registry to use urls package

This simply moves the registry app to be using the urls package and its
exported route names. This supports locking down exported route definitions for
use in client packages.