`containertool` should stream large blobs to and from the registry

`containertool` currently handles whole files, but all the processes involved (reading, creating the tar archive, gzipping and uploading) can be streamed, reducing resource requirements and latency.

Streaming could be added gradually in different areas:
* copying images from one repository to another - as bytes are received from the source, they are sent to the destination
* uploading resource bundles
* uploading the final application image

Start by tracing containertool’s current whole-file paths for copying images, uploading resource bundles, and uploading the final application image. Done means the selected area streams bytes through the registry instead of handling whole blobs, while preserving the existing transfer behavior.

Written by the indexing model from the issue text.