[Tizen][Runtime] Fix install an wgt app without application

element in config.xml will crashed.

According to
https://source.tizen.org/sites/default/files/page/tizen-2.2-wrt-core-spec.pdf
<tizen:application / > MUST occurrence one time.

So we should always parse tizen application handler for packaged
wgt application. If the we cannot find application element
in manifest data the parse should be failed and the installation
should be failed too.

Besides, in old logic the type_ of wgt app always set to
TYPE_UNKNOWN and AlwaysParseForType of TizenApplicationHandler
can not work will, so if the root element of manifest is 'widget'
, we regard the app type_ as TYPE_PACKAGED_APP.
according the comment, you should check whether <widget> is root element as well. Otherwise, you'll have bug if <widget> is wrongly as non-root element.