generalize for other content sources

[github-actions[bot]]

See https://github.com/operator-framework/rukpak/issues/164

https://github.com/timflannagan/rukpak/blob/8596bd58d6ec24bf9965ad5a3268031dd2210e34/internal/provisioner/plain/controllers/bundle_controller.go#L264

        return updateStatusUnpackFailing(u, fmt.Errorf("get bundle contents: %w", err))
    }

    // TODO: generalize for other content sources
    // See https://github.com/operator-framework/rukpak/issues/164
    bundleImageDigest, err := r.getBundleImageDigest(pod)
    if err != nil {
        return updateStatusUnpackFailing(u, fmt.Errorf("get bundle image digest: %w", err))

[github-actions[bot]]

Closed in 2166b326f600c76b73cbb907e41fddf0f81dbae9