transfer_service_spec.rb

AFAIK the only relevant place is Projects::CreateService, this gets
called when user creates a new project, forks a new project and does
those things via the api.

Also create k8s namespace for new group hierarchy
when transferring project between groups

Uses new Refresh service to create k8s namespaces

- Ensure we use Cluster#cluster_project

If a project has multiple clusters (EE), using Project#cluster_project
is not guaranteed to return the cluster_project for this cluster. So
switch to using Cluster#cluster_project - at this stage a cluster can
only have 1 cluster_project.

Also, remove rescue so that sidekiq can retry