Added pages & tabs to better separate UI
Activated inputs are now saved and loaded
Sound state is now displayed better, it includes missing file detection (exceptions are not yet handled)

• Using a MultiBinding and an IMultiValueConverter with an enum didn’t work for some reason
  New page: playbacks
• It shows all sounds, their current time
• Will need a redesign
• Pro tip: don’t call Dispatcher.Post in a method you called Dispatcher.Post in (it will keep updating the UI but prevents user input, you can’t even close the window normally)
  Did a bit of refactoring:
• AudioManager is now a service
• Removed the Host service, the desktop lifetime and the TopLevel will be injected
  Added an overlay when a file dialog is open (because unlike windows, not all OSes/desktop environments prevent interactions in this situation)