common-workstation: Remove services.syslogd.tty.

No longer in use, because it was pre-systemd NixOS.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
common-workstation: Fix VirtualBox host setting.

We no longer need to import .../programs/virtualbox.nix anymore, so
let's switch to the module option.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>