This patch restructures the bare platform in preparation for a
`Platform` kind of output from CUE in addition to the existing
`BuildPlan` kind.
This patch establishes a pattern where our own CUE defined code goes
into the two CUE module paths:
1. `internal/platforms/cue.mod/gen/github.com/holos-run/holos/api/v1alpha1`
2. `internal/platforms/cue.mod/pkg/github.com/holos-run/holos/api/v1alpha1`
3. `internal/platforms/cue.mod/usr/github.com/holos-run/holos/api/v1alpha1`
The first path is automatically generated from Go structs. The second
path is where we override and provide additional cue level integration.
The third path is reserved for the end user to further refine and
constrain our definitions.
This patch loops over every Gateway.spec.servers entry in the default
gateway and manages an ExternalSecret to sync the credential from the
provisioner cluster.
