cmd/cue: command to list packages

[myitcv]

Is your feature request related to a problem? Please describe.

Go has go list to list package information (see #2882 for a request to be able to list module versions - that issue could be merged into this one). Having a similar command in CUE would be generally incredibly useful.

Describe the solution you'd like

A cmd/cue command to list package information like go list.

Describe alternatives you've considered

There isn't a good solution here, save for manually gathering this information as a human. Which seems to be a shame when https://pkg.go.dev/cuelang.org/go/cue/build#Instance exists already.

Additional context

n/a