Deprecate use of blockstorage package

[hairyhum]

Currently for snapshot operations kanister uses blockstorage package, which has several providers abstracting away specific APIs.
Functions like CreateVolumeFromSnapshot use those providers.

Since introduction of CSI volume snapshots this functionality can be done via CSI apis instead of blockstorage providers. The functions currently using blockstorage package can be changed to use CSI and blockstorage package can be deprecated.

[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.