Integrate google/fscrypt into Ceph CSI KMS and encryption setup. Adds
dependencies to google/fscrypt and pkg/xattr. Be as generic as
possible to support integration with both RBD and Ceph FS.
Add the following public functions:
InitializeNode: per-node initialization steps. Must be called
before Unlock at least once.
Unlock: All steps necessary to unlock an encrypted directory including
setting it up initially.
IsDirectoryUnlocked: Test if directory is really encrypted
Signed-off-by: Marcel Lauhoff <marcel.lauhoff@suse.com>