A new "internal/kms" package is introduced, it holds the API that can be
consumed by the RBD components.
The KMS providers are currently in the same package as the API. With
later follow-up changes the providers will be placed in their own
sub-package.
Because of the name of the package "kms", the types, functions and
structs inside the package should not be prefixed with KMS anymore:
internal/kms/kms.go:213:6: type name will be used as kms.KMSInitializerArgs by other packages, and that stutters; consider calling this InitializerArgs (golint)
Updates: #852
Signed-off-by: Niels de Vos <ndevos@redhat.com>
