[M108 Migration][API] Provide ewk_context_tizen_app_version_set api

[M108 Migration][API] Provide ewk_context_tizen_app_version_set api

This patch is for the requirement:
Provide ewk setting api for widget version which be used for html5 video.

1.Provide ewk_context_tizen_app_version_set api for HBBTV,
  to set the value of widget version.
2.This api must be used after ewk_context_tizen_app_id_set or
  ewk_send_widget_info beacuse need drop the process privillages
  and set dynamic plugin.

Reference:
- https://review.tizen.org/gerrit/283610/

Change-Id: I67f644d3455af3d1ac939bbe316d64ee347a9911
Signed-off-by: Jie Zhang <jie137.zhang@samsung.com>