xserver-nodm-init: improvements from meta-oe

xserver-nodm-init: improvements from meta-oe

Bring in some changes from the meta-oe version of this script in order
to bring them closer together. (Unfortunately it does not completely
supersede the recipes in meta-oe - there is still some unification to be
done between x11-common and xserver-common.)

* Add systemd support (with extensions for ROOTLESS_X)
* Remove sudo from RDEPENDS_${PN} since this hasn't been used by this
  for a long time
* Rearrange recipe slightly to make the order logical

A couple of additional improvements at the same time:
* Use ROOT_HOME for root's home directory
* Set short description in SUMMARY instead of DESCRIPTION

(From OE-Core rev: d4f82500fb30e9e25b517e65c2bd72b3c2bad070)

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>