Redefine tier0 testing

As part of tier0 unification across the rhel-pt-gcc components
(RHEL-113756), redefine tier0 testing.

Replace the outdated reference to the public part of tier1 as well
as the selection of the tests. Technically, there will be no
difference to the previous state.

plans/ci.fmf

@@ -1,17 +0,0 @@
-summary: tier0 test plan
-execute:
-    how: tmt
-prepare+:
-  - how: shell
-    script:
-      - dnf config-manager --set-enabled '*CRB' || true
-      - dnf config-manager --set-enabled '*crb' || true
-      - dnf config-manager --set-enabled '*codeready*' || true
-      - dnf config-manager --set-enabled '*buildroot' || true
-
-adjust+:
-  - discover:
-      how: fmf
-      url: https://gitlab.cee.redhat.com/toolchain-qe/tests-from-fedora/annobin.git
-      filter: 'tag: CI-Tier-1'
-    when: distro == rhel

plans/tier0.fmf

@@ -0,0 +1,29 @@
+# Tier 0 test plan. It's actually Tier 1
+#   - limited to its public part
+#   - executed on the architecture at hand
+# When run by osci.tier0 on CentOS Stream or RHEL, it receives the following
+# context:
+#   arch=x86_64 (the architecture at hand, currently OSCI uses just x86_64)
+#   distro=rhel<M>.<m> (even for CentOS Stream builds)
+#   trigger=build
+
+summary: Tier 0 test plan
+discover:
+  - name: collect_info
+    how: shell
+    tests:
+      - name: /info/rpms
+        test: rpm -qa --last
+  - name: public_tests
+    how: fmf
+    url: https://gitlab.com/redhat/centos-stream/tests/annobin.git
+    filter: tier:1
+prepare:
+  - how: shell
+    script:
+      - dnf config-manager --set-enabled '*CRB*' || true
+      - dnf config-manager --set-enabled crb || true
+      - dnf config-manager --set-enabled rhel-buildroot || true
+      - dnf config-manager --set-enabled '*debuginfo*' || true
+execute:
+  how: tmt