Enable event handling for Ozone EFL

Enable event handling for Ozone EFL

Functionalities:
1) Bringup mouse, touch and HW-KB key input event capturing and forwarding.
2) Enable focus handling and keep browser and engine's focus in sync.
3) Unification of event handling code for both onscreen and offscreen.
4) ubrowser white screen and EWA window size issues are also fixed.

Reference base patch : https://review.tizen.org/gerrit/269026
(Also includes many other fixups and patch changes partially)

Change-Id: Id97fbdc94df8a77f659d7176d6dd4c15c40de43b
Signed-off-by: Gajendra N <gajendra.n@samsung.com>