Feature request: Add difference result view

[johschmitz]

Great App, found it in F-Droid!

I would like to suggest to add a difference result view showing how much more or less everyone paid compared to his part, like in Tricount. That view is also good for cross checking and remembering if anything is missing. With that I think the app would almost be feature complete.

It could be on the top of the balances tab for example or in a separate tab.