The Key Manager is used by several cinder services, and not just
cinder-api. For example, the cinder-backup and cinder-volume services
use the Key Manager to clone encryption keys. Moving the Key Manager
parameters from cinder::api to init ensures the settings are always
configured, even when the cinder-api service isn't included in the
deployment.
Closes-Bug: #1886081
Change-Id: Ie3c95da2c0dab83e3c4b7e10f8a3531301692da5