Evaluate device orientation and auto-rotate

[romangg]

When auto rotate is activate for an output the device orientation is evaluated for rotating the output. Currently this is done in the KDisplay daemon. We could provide it directly in Disman instead to make use of it without the KDisplay daemon running.

One small issue is that the current implementation uses Qt's device orientation interfaces but we want to reduce the Qt usage in Disman according to #1.

But it is only an internal detail, not in the API. For now let's just continue to use the Qt implementation therefore.