Delete unused .cirrus.yml

The Cirrus_CI was planned for testing FreeBSD, but never really used I
think. Currently it's not needed anymore, so remove it.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Tino Reichardt <milky-zfs@mcmilk.de>
Closes #17155
Closes #17535

.cirrus.yml

@@ -1,21 +0,0 @@
-env:
-  CIRRUS_CLONE_DEPTH: 1
-  ARCH: amd64
-
-build_task:
-  matrix:
-    freebsd_instance:
-      image_family: freebsd-13-5
-    freebsd_instance:
-      image_family: freebsd-14-2
-    freebsd_instance:
-      image_family: freebsd-15-0-snap
-  prepare_script:
-    - pkg install -y autoconf automake libtool gettext-runtime gmake ksh93 py311-packaging py311-cffi py311-sysctl
-  configure_script:
-    - env MAKE=gmake ./autogen.sh
-    - env MAKE=gmake ./configure --with-config="user" --with-python=3.11
-  build_script:
-    - gmake -j `sysctl -n kern.smp.cpus`
-  install_script:
-    - gmake install