Configures widget manager to store widget contents for serving

Changes the storage location so that widget contents can
be served easily via http rather then fetch via content
protocol (ContentProvider). Further investigation needed
if that change should replace the content provider in the
long term.

Jira issue: WP-895
Merge pull request #548 from mlasak/platform_changes_for_wrt2

Configures widget manager to store widget contents for serving