Add new hetzner-nixops-installer package.

This fixes a bunch of issues for the NixOps Hetzner backend, because over there,
it's quite difficult to export the references graph without either duplicaing
lots of code or make a bunch of workarounds.

A detailed description about how it works can be found in the
meta.longDescription attribute.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
Move nixpartHetzner into hetzner-nixops-installer.

This should keep all Hetzner/NixOps specific stuff in one place.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
hetzner-nixops-installer: Reset helper timestamps.

This should prevent some annoying messages such as:

tar: usr/bin/nix-build: time stamp 2013-07-09 07:45:19 is 0.159248271 s in the f
uture
tar: usr/bin/nix-channel: time stamp 2013-07-09 07:45:19 is 0.159088763 s in the
future
tar: usr/bin/nix-collect-garbage: time stamp 2013-07-09 07:45:19 is 0.15901664 s
in the future
tar: usr/bin/nix-copy-closure: time stamp 2013-07-09 07:45:19 is 0.158948028 s i
n the future
tar: usr/bin/nix-daemon: time stamp 2013-07-09 07:45:19 is 0.158888042 s in the
future

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