[Runtime] Support launch an url from launcher.

After commit 4f4eca4773e7e4a98dc0198fdca1bae1886c749e

We always compile a Shared Process Model binary for
tizen, and it always run as shared process model, so we cannot
launch a page with url like 'xwalk http://www.google.com'.

There is an easy way that we can support launch an url from
launcher, and create an temp app for url.

BUG=XWALK-2060
Is it by design? I can not understand why xwalk can not be used directly.