New look for preferences

We re-designed the Preferences section of the app to give you a better overview.

With all the ways to configure Curiosity to your individual preferences, the Preferences section was getting a bit full.

We split it into sections that you can navigate in the left sidebar (image), re-worked settings to make them easier to understand, and generally cleaned up.

You can still access Preferences in the same place as always (cog icon at the bottom of the left sidebar)... and now finding things should be a breeze.