Move the cluster bootstrap into the keys flake.

Bootstrapping the cluster needs access to secrets, so I am moving it into the keys flake.

nix/kubernetes/hosts/worker0/default.nix

@@ -102,7 +102,6 @@
     # nix.sshServe.enable = true;
     # nix.sshServe.keys = [ "ssh-dss AAAAB3NzaC1k... bob@example.org" ];
 
-    me.bootstrap.enable = true;
     me.dont_use_substituters.enable = true;
     me.minimal_base.enable = true;
     me.worker_node.enable = true;