Migrate storage from icarus to johnson

[wizzdom]

Since icarus is on its last legs, lets transfer its storage to johnson.

• We'll have to keep the permissions and directory structure the same or very similar so as not to break existing services
• Its probably easiest to create a seperate NFS share to serve the older contents to keep privilege separation and so we can migrate it gradually
• Nix boxes (motherlode and icarus), paphos, and login boxes (pygmalion and azazel) will have to be remounted against the nfs share on johnson in https://github.com/redbrick/nomad/tree/master/ansible
• the /oldstorage mounts on the aperture boxes will have to be updated

All that should remain on icarus is LDAP until that is also migrated to https://github.com/redbrick/nomad/