swift: refactor into module, add codfw

The new module is aptly named not swift but swift_new, it is transitional only
however. Initially only codfw is on swift_new and other clusters will be
migrated to the new module once codfw is up and running. At that point the
module can be renamed into 'swift' and the legacy removed.

Change-Id: I73499567e6b862933168ce295669c23b742d763f