(PUP-3644) Move urls to v3

This removes the "v1" HTTP API, which mounted
all of the various Puppet endpoints at "/" on the webserver.

In its place we now have the "v3" API, which includes
the versioned "/v3" prefix for all of the indirected URLs.
This causes an `already initialized constant HTTP` warning when the tests are run, since this constant is already defined in `v2/authorization_spec.rb`. Do we care?