bsf oci push authentication

[dr-housemd]

Currently, having a --push flag on bsf doesn't authenticate to OCI registry.
We're using skopeo for this, we should look into --authfile flag as described here.
We could have a similar flag in bsf . Also, in case the flag isn't passed- perhaps we should default to using ~/.docker/config.json as a lot of tooling relies/uses that.

[dr-housemd]

Currently, we found that Skopeo doesn't aim to respect docker's config file for authentication. Unfortunately, this implies that we cannot re-use existing creds user has containers/skopeo#1083 (comment) .

Right now, if a user wants to push an image with authentication, they've to load the image in their docker daemon/pod and then push it.

Short term, maybe we can accept an authfile argument that skopeo supports and use it to push image out. This does require user to be aware of skopeo and skopeo login, unfortunately.

Mid/long term, we could look into implementing skopeo login/logout as bsf subcommands. Alternatively, we could look into how we could push out a directory by utilising docker/config.json.

[dr-housemd]

Update- we've introduced a CLI flag called --dest-creds similar to skopeo. This allows to ad-hoc push images to registries, especially in CI.