Remove of redundant plans

plans/public.fmf

@@ -1,7 +0,0 @@
-summary: Test plan that runs all tests from tests repo.
-discover:
-    how: fmf
-    url: https://src.fedoraproject.org/tests/cyrus-imapd.git
-execute:
-    how: tmt
-

plans/tier1-internal.fmf

@@ -1,15 +0,0 @@
-summary: CI plan, picks Tier1 tests, runs in beakerlib.
-discover:
-  - name: rhel
-    how: fmf
-    filter: 'tier: 1'
-    url: git://pkgs.devel.redhat.com/tests/cyrus-imapd
-  - name: fedora
-    how: fmf
-    filter: 'tier: 1'
-    url: "https://src.fedoraproject.org/tests/cyrus-imapd.git"
-execute:
-    how: tmt
-adjust:
-    enabled: false
-    when: distro == centos-stream-9