Enable gating tests for pam

Resolves: rhbz#1962804

tests directoy already existed, but there was not gating.yaml. Added
passing rule for osci tier0 to execute the tests available in tests
directory.

Note the this directory does not exist in internal repo, but expect it
to sync after this or another MR is merged

gating.yaml

@@ -0,0 +1,7 @@
+--- !Policy
+product_versions:
+  - rhel-9
+decision_context: osci_compose_gate
+rules:
+  - !PassingTestCaseRule {test_case_name: osci.brew-build.tier0.functional}
+  - !PassingTestCaseRule {test_case_name: baseos-ci.brew-build.tier1.functional}