Update gating (tier0) configuration

- Fix setup
- Use less tests in tier0, all those I'm filtering out now
  are used in later phases of CI anyway

plans/ci.fmf

@@ -1,6 +1,22 @@
-summary: CI Gating Plan
-discover:
-    how: fmf
-    url: https://src.fedoraproject.org/tests/annobin.git
+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://src.fedoraproject.org/tests/annobin.git
+      filter: 'tag: CI-Tier-1'
+    when: distro != rhel
+  - discover:
+      how: fmf
+      url: https://gitlab.cee.redhat.com/toolchain-qe/tests-from-fedora/annobin.git
+      filter: 'tag: CI-Tier-1'
+    when: distro == rhel