Rework the HotkeyManager and KeyboardHook interop classes (#4710)

* Use GetAsyncKeyState calls and remove additional thread usage

* Removed Environment.Exit

src/core/Microsoft.PowerToys.Settings.UI.Runner/Program.cs

@@ -74,9 +74,6 @@ namespace Microsoft.PowerToys.Settings.UI.Runner
                         MessageBoxButton.OK);
                     app.Shutdown();
                 }
-
-                // Terminate all threads of the process
-                Environment.Exit(0);
             }
         }