#
  # Figure out what root pubkey(s) to use. Originally, we just copied over
  # *.pub, but that gets a whole lot of weird crap on the mothership. So now
  # we try to be more selective:
  #
  # To keep up with the cool kids, we want to use an Ed25519 key
  # (id_ed25519.pub) if possible.
  #
  # However since ed25519 is not supported by older sshds, we better have
  # an RSA alternative (id_rsa.pub) as well.
  #
  # But that key may be really old and less than 2048 bits, so we may have
  # a bigger one as well (id_rsa_new.pub, note: requires changing the default
  # ssh_config on your boss since this is not a default key file name to try).
  #
  # We really don't want to use a DSA key (id_dsa.pub) anymore unless there
  # is no alternative.
  #
  # Finally, if we are an Elabinelab setup, include the outer boss root key.
  #