fix(spindle): persist data

Spindles don't really like it when you delete their state every
time they turn on. It tends to lead to lost logs and repulled nixery
containers. Let's fix that...

packetmix/systems/midnight/spindle.nix

···
     };
     pipelines.workflowTimeout = "2h";
   };
+
+  clicks.storage.impermanence.persist.directories = [ "/var/lib/docker" "/var/lib/spindle" ];
 }