Settings: Add DPI Scaling Entries

* Take DPI and PixmapFactor from luna.conf & use to calculate scale

Open-WebOS-DCO-1.0-Signed-Off-By: Josh Palmer <jpalmerwatkins@me.com>
Merge branch 'webOS-ports/master-next' into webOS-ports/master
Add settings entry for setting different DPI for some applications

Signed-off-by: Simon Busch <morphis@gravedo.de>