Improve missing API group/kind message

[willthames]

e.g. if trying to import a Deployment that was last configured
using extensions/v1beta1, the error message improves from:

Error: Cannot import non-existent remote object

While attempting to import an existing object to "kustomization_resource.p1["apps/Deployment/test-ns/test-deploy"]",
the provider detected that no object exists with the given id. Only pre-existing objects can be
imported; check that the id is correct and that it is associated with the provider's configured
region or endpoint, or use "terraform apply" to create a new remote object for this resource.

to:

Error: github.com/kbst/terraform-provider-kustomize/kustomize.kustomizationResourceExists: Can't find Deployment in API group extensions