Rework "datamover" component responsible for exporting data to the object store

[hairyhum]

This is an umbrella issue for multiple things to do in order to change the way kanister integrates with tools like kopia or restic.

• New datamover design doc: docs: Datamover abstraction design doc #3389
• Extend configurations for MultiContainerRun and KubeTask to support more complex workflows: TODO
• Create kopia datamover client implementation: TODO
• Create kopia datamover server implementation: TODO
• Create an example blueprint using "datamover" export: TODO
• Deprecate restic in favour of kopia: Datamover: deprecate restic in favour of kopia #3485

[github-actions]

Thanks for opening this issue 👍. The team will review it shortly.

If this is a bug report, make sure to include clear instructions how on to reproduce the problem with minimal reproducible examples, where possible. If this is a security report, please review our security policy as outlined in SECURITY.md.

If you haven't already, please take a moment to review our project's Code of Conduct document.