Migrate to TMT-style gating in C9S

This is required for RHIVOS, see VROOM-23635.

(The "ci" directory is intentionally left intact, since it's apparently
not included in the dist-git exclude hook and would require a valid Jira
ticket to be linked to.)

ci.fmf

@@ -1,14 +1 @@
-/test:
+resultsdb-testcase: separate
-    summary:
-        Basic set of quick tests for cpio.
-    discover:
-      - name: fedora
-        how: fmf
-        filter: "tag: Tier1,Tier2,Tier3 & distros: fedora"
-        repository: "https://src.fedoraproject.org/forks/odubaj/tests/cpio.git"
-    prepare:
-        how: ansible
-        playbooks:
-            ci/fedora-rawhide.yml
-    execute:
-        how: beakerlib

gating.yaml

@@ -1,6 +1,6 @@
 --- !Policy
 product_versions:
-  - fedora-*
+  - rhel-9
-decision_context: bodhi_update_push_stable
+decision_context: osci_compose_gate
 rules:
-  - !PassingTestCaseRule {test_case_name: baseos-ci.koji-build.tier1.functional}
+  - !PassingTestCaseRule {test_case_name: osci.brew-build./plans/tier1-internal.functional}

plans/tier1-internal.fmf

@@ -0,0 +1,11 @@
+summary: Internal gating tests plan
+discover:
+  - name: Internal gating tests
+    how: fmf
+    filter: 'tag: Tier1,Tier2,Tier3'
+    url: https://pkgs.devel.redhat.com/git/tests/cpio
+execute:
+    how: tmt
+adjust:
+    enabled: false
+    when: distro == centos-stream or distro == fedora

tests/tests.yml

@@ -1,17 +0,0 @@
-# This package uses external repositories for maintaining CI test cases.
-# Please don't edit this file if possible.
-
-# TODO: minimize according to
-# https://pagure.io/standard-test-roles/issue/294
-
-- hosts: localhost
-  roles:
-  - role: standard-test-beakerlib
-    repositories:
-    - repo: https://src.fedoraproject.org/forks/odubaj/tests/cpio.git
-      dest: cpio
-      fmf_filter: "tag: Tier1,Tier2,Tier3"
-    tags:
-    - classic
-    - container
-    - atomic