So many times people are not aware of the --verbose option, because exposing
only an array of stringsmeans you need to go check the vlc cli page for
information.
Having an enum explicitly for this makes it discoverable from the VS
intellisense. It may be good to have it enabled by default.

# Conflicts:
#	samples/LibVLCSharp.Mac.Sample/ViewController.cs
#	samples/LibVLCSharp.iOS.Sample/ViewController.cs
#	samples/LibVLCSharp.tvOS.Sample/ViewController.cs
#	samples/Uno/LibVLCSharp.Uno.Sample.Shared/MainViewModel.cs
#	samples/Uno/Sample.MediaPlayerElement/Sample.MediaPlayerElement.Shared/MainViewModel.cs