CSI: Support for device mode volumes

[endocrimes]

Currently we've only really been testing CSI for filesystem mounts and not devices.

We need to add support for mounting devices as part of shipping CSI. The "easiest" way to begin is probably "trying to run a job that requires one" repeatedly until you make it work, but the primary places to update will be:

• taskrunner/volume_hook: This will need to generate drivers.DeviceConfig's for volumes where IsDevice is true. You'll also need to make sure these propagate to drivers correctly.
• allocrunner/csi_hook: We may need to generate different paths for volumes that desire a device attachment mode.

[tgross]

I took a quick look through some of the CSI providers in kubernetes-sigs and it looks like BlockVolume (device) support isn't yet implemented for all the storage providers . I'm wondering if it might make sense for us to ship 0.11 with support only for MountVolume and then add BlockVolume support in a point release? Do you have a better understanding of whether this should be treated as a show-stopper?

[endocrimes]

@tgross I'd personally be fine with deferring it but we should probably run that by @yishan-lin because the PRD had it as part of the success criteria so there may be some downstream communication required.

[tgross]

Doing some issue cleanup. It looks like we've resolved this with the work we did to validate VolumeCapabilities in #7831 and fixing the target path in #8505, and I've had working tests with DO volumes in block-device mode. Going to close this out.

[github-actions]

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