Support loading for app:// scheme and widget:// scheme.

Support loading for app:// scheme and widget:// scheme.

WRT should use protocol for app:// scheme or widget:// scheme.
So we added the new alternativeURL variable to resourceRequestBase class to support app:// and widget:// protocol loading.
Also the changed data:// protocol from file:// protocol is supported.

[Title] Support loading for app:// and widget:// scheme.
[Issue#] N/A
[Problem] The app:// , widget:// protocol is not supported.
[Cause] app:// , widget:// scheme is not supported protocol in webkit.
[Solution] Add the new alternativeURL variable to resourceRequestBase class and if the original url is app:// scheme then replace it to file:// or data:// scheme before request.
[SCMRequest] N/A

Change-Id: I0adf59337a17be36cb65e8ffad13642659fce48a