RequirementsAuthority multi role support enhancement

This patchset eliminates different behaviour between
policy_authority and requirements_authority.

Problem description:

`rbac_test_roles = [member,]`

Policy authority:

`update_port: role:member and role:viewer`

Results in 403/False (we are member but not viewer).

Requirements authority:

```
req_auth:
    update_port:
        - member
        - viewer
```

Results in 200/True (member in update_port list).

Proposed solution:

Change requirements_authority file sytax to support
comma separated roles to be considered as logical and.

Depends-On: https://review.openstack.org/#/c/606110/
Change-Id: I2e2a4a2020f5e85af15f1836d69386bc91a2d2ec
Co-Authored-By: Felipe Monteiro <felipe.monteiro@att.com>
5 files changed