Migrate to TMT-style gating in C9S

This is required for RHIVOS, see VROOM-23635.

.fmf/version

@@ -0,0 +1 @@
+1

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: baseos-ci.brew-build.tier1.functional}
+  - !PassingTestCaseRule {test_case_name: osci.brew-build./plans/tier1-internal.functional}

plans/tier1-internal.fmf

@@ -0,0 +1,15 @@
+summary: Internal gating tests plan
+discover:
+  - name: Internal gating tests (gmp)
+    how: fmf
+    filter: 'tag: CI-Tier-1'
+    url: https://pkgs.devel.redhat.com/git/tests/gmp
+  - name: Internal gating tests (nettle)
+    how: fmf
+    filter: 'tag: CI-Tier-1 & component: gmp'
+    url: https://pkgs.devel.redhat.com/git/tests/nettle
+execute:
+    how: tmt
+adjust:
+    enabled: false
+    when: distro == centos-stream or distro == fedora