refactor(authz): use a struct for user access control info operations (#1682)

fix(authz): fix isAdmin not using groups to determine if a user is admin.
fix(authz): return 401 instead of 403

403 is correct as per HTTP spec
However authz is not part of dist-spec and clients know only about 401
So this is a compromise.

Signed-off-by: Petu Eusebiu <peusebiu@cisco.com>

.github/workflows/ecosystem-tools.yaml

@@ -78,6 +78,9 @@ jobs:
       - name: Run push-pull tests
         run: |
             make test-push-pull
+      - name: Run push-pull-authn tests
+        run: |
+            make test-push-pull-authn
       - name: Run metrics tests
         run: |
             make test-bats-metrics