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 service token feature
Note that the credential parameters for authtoken middleware are
used in some providers, and these providers still require a project
scope credential. This will be fixed by the subsequent change.
Depends-on: https://review.opendev.org/804325
Change-Id: I33f912aeb058fd269d4a0eda57438051a2f094ff
0256c26d21