Use DEKStore API for Fetching and Storing passphrases.
Drop the fallback for the old KMS interface that is now provided as
DEKStore. The original implementation has been re-used for the DEKStore
interface.
This also moves GetCryptoPassphrase/StoreNewCryptoPassphrase functions
to methods of VolumeEncryption.
Signed-off-by: Niels de Vos <ndevos@redhat.com>
Prepare for grouping encryption related functions together. The main
rbdVolume object should not be cluttered with KMS or DEK procedures.
Signed-off-by: Niels de Vos <ndevos@redhat.com>
Prepared for an enhanced API to communicate with a KMS and keep the DEK
storage separate. The crypto.go file is already mixed with different
functions, so moving the KMS part into its own file, just like we have
for Hashicorp Vault KMS's.
Signed-off-by: Niels de Vos <ndevos@redhat.com>
