✨ Add disk encryption key to GCP compute disks

[imilchev]

./cnquery run gcp -c "gcp.project.compute.disks{name diskEncryptionKey}"                                                                                                                                                   
→ discover related assets for 1 asset(s)
→ resolved assets resolved-assets=1
gcp.project.compute.disks: [
  0: {
    diskEncryptionKey: {}
    name: "gke-mondoo-gke-cluster-2-generic-pool-738078cc-1bdm"
  }
  1: {
    diskEncryptionKey: {}
    name: "gke-mondoo-gke-cluster-2-generic-pool-738078cc-fhgp"
  }
  2: {
    diskEncryptionKey: {}
    name: "test-other-zone"
  }
]