Add test plan to run rust-afterburn gating tests in c9s

Ref: https://issues.redhat.com/browse/COS-2285
Upstream PR : https://github.com/coreos/afterburn/pull/1218

.fmf/version

@@ -0,0 +1,2 @@
+1
+

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}   # this is the testcase identifier, which OSCI pipeline uses
+  - !PassingTestCaseRule {test_case_name: osci.brew-build./tests/tmt/plans/smoke}   # this is the testcase identifier, which OSCI pipeline uses

plans/main.fmf

@@ -0,0 +1,9 @@
+prepare:
+  - name: Install afterburn package
+    how: install
+    package: afterburn
+  - name: Set AFTERBURN_BIN_DIR when installed package
+    how: shell
+    script: |
+      set -x -e -o pipefail
+      echo "AFTERBURN_BIN_DIR=/usr/bin" > /tmp/afterburn_bin_dir

plans/smoke.fmf

@@ -0,0 +1,9 @@
+summary: Run gating tests 
+discover:
+    - name: Internal gating tests
+      how: fmf
+      url: https://github.com/coreos/afterburn.git
+      filter: 'tag: smoke'
+execute:
+    how: tmt
+