This commit adds a validation step in the auth_token middleware to check
for the presence of an access_rules attribute in an application
credential token and to validate the request against the permissions
granted for that token. During token validation it sends a header to
keystone to indicate that it is capable of validating these access
rules, and not providing this header for a token like this would result
in the token failing validation. This disregards access rules for a
service request made by a service on behalf of a user, such as nova
making a request to glance, because such a request is not under the
control of the user and is not expected to be explicitly allowed in the
access rules.
bp whitelist-extension-for-app-creds
Depends-On: https://review.opendev.org/670377
Change-Id: I185e0541d5df538d74edadf9976b3034a2470c88
5f093bf5ee