[3D] move logic to invert stereomodes to manager so that it can be more easily reused
[3D] fix resolution and aspect of stereoscopic videos in case of missing or wrong metadata
[3D] move logic to resolve the stereomode of a CFileItem or path to manager
[3D] add public setter for stereomode in stream details as well as a helper method to do so in manager
[3D][WIP] make streamdetails only source for stereomode and make videosettings change stereomode instead of setting