Migrate to TMT-style gating in C9S

This is required for RHIVOS, see VROOM-23635.

ci.fmf

@@ -0,0 +1 @@
+resultsdb-testcase: separate

gating.yaml

@@ -3,4 +3,4 @@ product_versions:
   - rhel-9
 decision_context: osci_compose_gate
 rules:
-  - !PassingTestCaseRule {test_case_name: osci.brew-build.tier0.functional}
+  - !PassingTestCaseRule {test_case_name: osci.brew-build./plans/libpsl-all-internal.functional}

plans.fmf

@@ -0,0 +1,7 @@
+# libpsl uses publicsuffix-list in its test suite, so use it to verify
+# publicsuffix-list as well
+/libpsl-all-internal:
+  plan:
+    import:
+      url: https://pkgs.devel.redhat.com/git/tests/libpsl
+      name: /plans/all

plans/tests.fmf

@@ -1,19 +0,0 @@
-summary:
-    Run tests from the libpsl repository
-
-discover:
-    how: fmf
-    url: git://pkgs.devel.redhat.com/rpms/libpsl
-    ref: rhel-8.6.0
-
-prepare:
-    - name: data
-      how: install
-      package: publicsuffix-list
-
-    - name: bin
-      how: shell
-      script: dnf install -y --enablerepo=rhel-buildroot psl
-
-execute:
-    how: tmt