make oobe layout partially scalable

make oobe layout partially scalable

This is 1st stage of making OOBE Layout scalable
across various resolutions. This patch makes ui
scale well across 1280x720 and 1280x800 resolutions.

Supporting other resolutions will require some more work
and will be added later, after deciding which elements
should scale with resolution increase and which not.

This patch also removes some duplicated code and make
future changes easier.

Change-Id: I412af147d66825e2558f81e8b11803267942b0c7