Add --image-name-with-digest-file

[Ark-kun]

I request a small new feature very similar to the existing --digest-file option.
The --digest-file option only outputs the image digest (sha256:bc45...67e1) and needs to be combined with image name to make a working image reference.

The --image-name-with-digest-file should output the full image name including the digest: my-org/my-image@sha256:bc45...67e1

[tejal29]

@Ark-kun, since the user specifies the image name in the --destination flag, can you write a script to append the image name?

[Ark-kun]

can you write a script to append the image name?

I tried that, but the Kaniko container image is distroless and does not have sh.

Generally, I think that the full image name is more useful than just digest alone.