Incremental Source Upload

[otaviof]

To improve the user experience when shp build upload for a big repository, we should support incremental uploads.

In high level, that means having a PVC mounted on /workspace/source instead of the emptyDir: {} currently employed. On the CLI side, using the incremental rsync protocol.

For the persistent volume under /workspace/source, we have SHIP-0022 covering volumes for a BuildStrategy and the issue-478 to consider.

[qu1queee]

From grooming, keeping this one open for more discussions. There might be an interjection on this between upload and bundle for local source.

[adambkaplan]

Changing the upload mechanism requires coordination with the build controller and potential API changes. Therefore it requires a SHIP.