Implement a registry:// alias for docker://

[mtrmac]

Concerns:

• Need to ensure the configuration in policy.json is not ambiguous; that ambiguity check currently exists at transport-level, this requires some kind of merging.
• The // are ugly noise, OTOH may be necessary to disambiguate short names in Podman (registry:2 == “the short name registry:2 vs. registry:busybox == docker://busybox:latest). Previously #1003 .

[rhatdan]

I am looking forward to this change.

[vrothberg]

Tackling it now o/

[rhatdan]

Awesome, This would make me very happy.