Fully exit Motrix on pressing close

[Apacelus]

Is your feature request related to a problem? Please describe. When I am done downloading a file and I close motrix, it keeps running in the background.

Describe the solution you'd like I would suggest to make an option to quit motrix enterely when all active downloads have been finished and the user clicks the cross to exit Motrix.

Describe alternatives you've considered N/A

Additional context Similar to how other apps have it(like Microsoft Teams or Skype)

[Chrysanthemum536]

please add this option