Task skopeo-copy should support copying to/from image archives

[bparry02]

skopeo can be used to copy images to/from archives, and this is a valid use case for the Tekton task as well. For example, if a user needs to "import" an image from a tarball to a registry, or "export" one to disk.

The current task implementation almost supports this, but the following changes must be made:

1. Add an optional workspace to copy image archives to/from.
2. Add an optional boolean parameter to set the --remove-signatures skopeo option. This is required for copying to the oci-archive type.

Additional Info

---
apiVersion: tekton.dev/v1
kind: TaskRun
metadata:
  name: skopeo-copy-taskrun
spec:
  params:
    - name: srcImageURL
      value: 'docker://registry.access.redhat.com/ubi9/ubi:9.7'
    - name: destImageURL
      value: 'oci-archive:/workspace/image-archive-dir/ubi-9.7.tar'
    - name: removeSignatures
      value: 'true'
  taskRef:
    kind: Task
    name: skopeo-copy
  workspaces:
    - name: image-archive-dir
      persistentVolumeClaim:
        claimName: shared-data-workspace