Some major platform-dependent file operations refactoring.
All methods like "open file", "open file with", "show in folder"
were moved to core/file_utilities module with platform-dependent
backends. All methods interacting with DesktopServices made async.
OnPropertyValueChanged() is called sometimes couple times a second
and sometimes when AudioMutex is locked already causing a deadlock.
Also some code added to support Desktop Bridge converter to UWP app.