add temporary docker cleanup cron

sn06.yml

@@ -132,6 +132,12 @@
         - "ecdsa-sha2-nistp521 AAAAE2VjZHNhLXNoYTItbmlzdHA1MjEAAAAIbmlzdHA1MjEAAACFBABRaLHL8mgW86rbtdUh6TY4rs7/la8hAGeSQ3jBF7LMwYZnbS32YDMYvDq3KgNu5WqSMFvkxNm3vfTAbd8CXBfakwDBFBaD9kO0b2t4/p4VoFUsd3B2OvmTR7Bsg7OxTGJJ7aUP/SzTg+Z4NzsmHwQ9h31gfI7n/buZD4S1edQke19Y6w== dominguj@informatik.uni-freiburg.de"
         - "ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAACAQC3UNEZrYCERrpZl/NzL9/q2dOyJJT0Ini6AEmFyPubh6yaVf4Iko+8MVYUx92RKuaY5bE8cC7JcLRZMKZ2lPVkP5tUUwILl2d2/sWlHnyZ1oGdOTfPB6b+boDansJcm3HnREO7umAqgbUErahWIDWOk3SPXOxirqsWrElNm5pKr8Ng8KWz9Ht9/J0oDxPxwYQcz64ogT7ERtCn3+UoEM/XQ4iVHvAk/rwLev8symd5SzrxFt6nI2vqduFBEMoA2VTISuI0rYVFqYpQ7I4QxOl5GbNHUeuvB5+YKh5P2QAi9mOPdp8MO2ZJnjtT+x7EgJKXHu2EBKDwW/93bPfL5SGFUK80HSyYG8sicSYpAUk1asE+T90QvpGUrXPaIabWXHvhj7vq7Y6l103o9T4N2qCpe8e4e3WthGzYu9Tfau7vko7pd+F7rnkvjvmj+WmSJPv+jadpMDyiUyYEIj4ncik89FOWIzt/IYYiC+po6nmD1del4s0Zenr2gEEsjyhvOiPLI7+Bw+w4m/xiHvlP1s40ZtIsUhwOYBEQUbfoHG0zR4jIgD8h/VA47oAvkNDGKJpkEbXpRpUtQxJLDNcnUFjEG86+NGWOuXzwllrH80TFueSFVg9dHu8d5Jx5m9LeZbf+vRnpSpIgQlVR/C4hFFYtK44/Daz+TqOXMgQqabypfQ== catherine.bromhead@unimelb.edu.au"
         - "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIPzm/ZHp+16Oz/5TbQkJZMC5yvp/C3OfvgOlRWqEX/Fc jdavcs@gmail.com"
+    - name: Set temporary cron for cleaning docker images
+      ansible.builtin.cron:
+        name: "Temporary docker cleanup – needs upstream fix see issue #584"
+        minute: "0"
+        hour: "4"
+        job: "/bin/docker system prune --all > /dev/null"
   roles:
     ## Starting configuration of the operating system
     - role: usegalaxy_eu.handy.os_setup