DocumentsUI: Allow open files instead of URIs

Check files' real path and mime type to open them only in standalone mode.
This allows, for example, installing apks.

Change-Id: I4501c694db84b8595cd3928752254a8914539972
base: added national roaming for 3AT on orange austria
Users of 3AT (MCC 232 MNC 11) can roam on Orange (MNC 05)

Change-Id: I6c0823acda265faca3bf3a851cbec8b848668b2a