Add TMT test infrastructure for conmon

Add .fmf/, plans/, and tests/ directories to enable automated
tier0 testing in the RHEL-on-GitLab MR pipeline. Port TMT
configuration from rhel-9.8.0 branch, updated to reference
c10s branch of the test repository.

Also add tier0 gating rule to gating.yaml.

Resolves: RHEL-180349

plans/conmon.fmf

@@ -0,0 +1,27 @@
+---
+summary: Run conmon tests
+description: Test plan for conmon
+contact: jnovy@redhat.com
+
+discover:
+    how: fmf
+
+provision:
+    how: artemis
+
+prepare:
+    - how: install
+      package:
+        - crun
+        - podman
+        - podman-tests
+        - git
+    - how: shell
+      script: |
+        BATS_VERSION=1.11.0
+        curl -L https://github.com/bats-core/bats-core/archive/refs/tags/v$BATS_VERSION.tar.gz | tar zx
+        cd bats-core-$BATS_VERSION
+        ./install.sh /usr
+
+execute:
+    how: tmt