Remove CirrusCI-based FreeBSD CI.

It doesn't seems to be used by anyone, so don't waste Cirrus resources.

.cirrus.yml

@@ -1,24 +0,0 @@
-task:
-  freebsd_instance:
-    matrix:
-      - image_family: freebsd-13-1-snap
-  env:
-    # /usr/ports/Mk/Uses/localbase.mk localbase:ldflags
-    LOCALBASE: /usr/local
-    CFLAGS: -isystem $LOCALBASE/include
-    CPPFLAGS: $CFLAGS
-    CXXFLAGS: $CFLAGS
-    LDFLAGS: -L$LOCALBASE/lib
-  deps_script:
-    - sed -i.bak -e 's/quarterly/latest/' /etc/pkg/FreeBSD.conf
-    - pkg install -y meson pkgconf git-lite dbus glib libepoll-shim libudev-devd vulkan-loader vulkan-headers v4l_compat gstreamer1 gstreamer1-plugins libinotify gettext libsndfile sdl2 alsa-lib
-    - sysrc dbus_enable=YES
-    - service dbus restart
-  build_script:
-    - mkdir build
-    - cd build
-    - meson setup -Dalsa=enabled -Draop=enabled -Dv4l2=enabled -Dpipewire-alsa=enabled -Dbluez5=disabled -Djack=disabled -Dpipewire-jack=enabled -Dpw-cat=enabled -Dpipewire-v4l2=disabled -Dsdl2=enabled -Dsystemd=disabled -Dsession-managers=media-session ..
-    - ninja
-  test_script:
-    - cd build
-    - ninja test