Improve output of multiple screen resolution

Improve output of multiple screen resolution

To improve output on various monitor with various resolution,
the following items are introduced.

 * Abandon scaling by Weston/IVI-SHELL
   This is cause of huge memory consumption on AGL CES2018 Demo
   because all contents are designed and rendered with FullHD
   resolution.

 * Add parameter of 'scale' to WM API (getDisplayInfo)
   WM calculate scale factor from screen resolution from wayland
   compositor and parameter of layout from WM's configuration,
   area.db.

Bug-AGL: SPEC-1568, SPEC-1569, SPEC-1611

Change-Id: I5eac2da0106228c296550135c5200b2653864fdf
Signed-off-by: Tadao Tanikawa <tanikawa.tadao@jp.panasonic.com>