[M108 Migration][WRTjs][VD] Merge splash screen feature

[M108 Migration][WRTjs][VD] Merge splash screen feature

1.Support landscape/portrait splash screen
landscape/portrait splash screen should be supported.
https://docs.tizen.org/application/tizen-studio/web-tools/config-editor/#tizen-launch-screen-2
<tizen:launch_screen ready_when="custom">
  <tizen:ls_default background_color="#00ff00" image="images/default.png" image_border="0px stretch"/>
  <tizen:ls_landscape background_color="#ff0000" image="images/landscape.png" image_border="0px stretch"/>
  <tizen:ls_portrait background_color="#0000ff" image="images/portrait.png" image_border="0px stretch"/>
</tizen:launch_screen>

2.splash screen image support SHARE path
LYNKCloud app need to download splash screen image from server.
They save image to SHARE path(/opt/usr/home/owner/share),
WRT set this image as splash screen image.

Reference:
https://review.tizen.org/gerrit/289862/
https://review.tizen.org/gerrit/289246/

Change-Id: I4cf8d770e2698af9c40a6e8242da109d048098e1
Signed-off-by: zhaosy <shiyusy.zhao@samsung.com>