Refactor cellv2 host discovery logic to avoid races

Refactor cellv2 host discovery logic to avoid races

The compute service list is polled until all expected hosts are reported or a
timeout occurs (600s).

Adds a cellv2_discovery flag to puppet services. Used to generate a list of
hosts that should have cellv2 host mappings.

Adds a canonical fqdn and that should match the fqdn reported by a host.

Adds the ability to upload a config script for docker config instead of using
complex bash on-liners.

Closes-bug: 1720821
Change-Id: I33e2f296526c957cb5f96dff19682a4e60c6a0f0
(cherry picked from commit 61fcfca045aeb5be1ee280d8dd9c260fb39b9084)