Clean up layouts

  Use Start/End instead of Left/Right for better
  compat.
  Use layouts based of the center of the screen
  for better maths
  Clean up layouts/paddings/margins

  This should keep the layouts for overlapping on certain
  devices.

  TODO: add layouts for other screen types.

Signed-off-by: KhasMek <Boushh@gmail.com>
layout: remove unused values

Signed-off-by: KhasMek <Boushh@gmail.com>
layout: add sw600dp

Signed-off-by: KhasMek <Boushh@gmail.com>