lxd/storage/drivers/driver/ceph/volumes: Reworks SetVolumeQuota to be more aligned with LVM driver structure
lxd/storage/drivers/driver/ceph/volumes: Reworks SetVolumeQuota to be more aligned with LVM driver structure

 - Performs content type resize logic first rather than shrink/grow logic first.
 - Adds support for Volume's in-use detection.

Signed-off-by: Thomas Parrott <6b778ce645fb0e3dde76d79eccad490955b1ae74@canonical.com>

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