App refinements, Google sign-in and legal — Patch notes

Added Google sign-in alongside Discord
Added Terms of Service and Privacy Policy dialogs (see Login and Settings)
Login page now requires agreeing to terms via checkbox
Landing-style login layout and improved Discord button styling
Optimized loading performance for faster access and reduced amount of data transferred
Fixed bugs where the metrics where showing some wrong values
Sparklines added to sales overview
Export CSV can export sales, expenses and monthly reports for any date range
Differentiated item fees and general expenses in reports