This change is the first step to support secure RBAC and allows usage
of system scope credentials for Keystone API request.
This change covers the following three items.
- assignment of system scope roles to system user
- credential parameters for authtoken middleware
- credential parameters for s3token middleware
- credential parameters for ceilometer middleware
Depends-on: https://review.opendev.org/804325
Change-Id: I1923a5aed12a503f450c7d2e4a7784e4746fb46c