The Makefile was previously changed to install the scripts according to
the /usr merge. As the service files point to the scripts, the paths
need to be adapted there as well.

`make install` will now install both openrc and systemd service files.

The rationale behind this change is that packaging in distros can choose
how they include/exclude stuff. E.g. in pmOS/Alpine, the -openrc abuild
split function would stuff the openrc files into -openrc, and some
future -systemd split function () would move the systemd unit files to
some -systemd subpackage

PREFIX was dropped and paths updated so that they
were compliant with a merged /usr layout.

This adds two systemd services files that are responsible for starting "swclock-offset-boot" during boot and "swclock-offset-shutdown" when the system is shutting down.

Signed-off-by: Darrel Griët <dgriet@gmail.com>
Co-authored-by: Jakob Hauser <jahau@rocketmail.com>

Add initial files to repository

See merge request !1