First steps towards QBatteryInfo Refactorization

-Remove the QML wrapper registration temporarily
-Change the public API to lock it to one index
-Change the Linux private API to lock it to one index
-Change the Mac private API to lock it to one index
-Change the Windows private API to lock it to one index
-Change the tests to use the new API
-Change the Simulator private API to lock it to one index

Change-Id: I5b3d36a3baad339623281d79014c411c59dd1b59
Reviewed-by: Andrew Wooster <awooster@blackberry.com>
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>