Optionally expose all underlying container metadata in status

As someone deploying a bootc system, I may want to add custom labels (or OCI annotations) into my image, and I want to be able to see that on the client side to potentially act on it.

Today this is all squirreled away in the underlying ostree-container store, one can extract it with `ostree container metadata`, but that's awkward and we want to get away from exposing ostree (this also relates to https://github.com/containers/bootc/pull/215 )

Maybe what we do for now is something like `bootc status --full` which would dump the container manifest and config into the image status?

Start by reading the existing `bootc status` behavior and comparing it with `ostree container metadata`, including the proposed `bootc status --full` direction. Clarify the output contract for exposing the container manifest, config, custom labels, and OCI annotations; done means the agreed metadata is available on the client side without requiring direct ostree access.

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