gluon-authorized-keys: Force installation of gluon-lock-password

The gluon-authorized-keys is usually installed to use SSH keys to
authenticate a user against the device. To make this useful, it is also
required to disable passwordless SSH access to the device.

This new dependency is only required when the user doesn't have
gluon-setup-mode enabled already.

Fixes: #1777
Reported-by: yanosz <github@yanosz.net>
Fixes: a753fa79 ("gluon-authorized-keys: add keys from site.conf")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
(cherry picked from commit 2eb15bac0e974385b6b49d3c9e74f623d3d63c3f)