Persist API data

lib/models/counts_by_hour.dart

lib/models/discoveries.dart

lib/models/statistics_global.dart

lib/models/statistics_recent.dart

lib/models/timeline.dart

lib/models/topartists.dart

lib/ui/widgets/app_bar.dart

lib/ui/widgets/cards/counts_by_day.dart

lib/ui/widgets/cards/counts_by_hour.dart

lib/ui/widgets/cards/discoveries.dart

lib/ui/widgets/cards/statistics_global.dart

lib/ui/widgets/cards/statistics_recent.dart

lib/ui/widgets/cards/timeline.dart

lib/ui/widgets/cards/top_artists.dart

lib/ui/widgets/content/statistics_global.dart

lib/ui/widgets/content/statistics_recent.dart

lib/ui/widgets/update_data.dart

pubspec.yaml