Normalize game architecture

lib/ui/screens/page_about.dart

lib/ui/screens/page_game.dart

lib/ui/screens/page_settings.dart

lib/ui/settings/settings_form.dart

lib/ui/settings/theme_card.dart

lib/ui/skeleton.dart

lib/ui/widgets/actions/button_delete_saved_game.dart

lib/ui/widgets/actions/button_game_quit.dart

lib/ui/widgets/actions/button_game_start_new.dart

lib/ui/widgets/actions/button_resume_saved_game.dart

lib/ui/widgets/game/cell.dart

lib/ui/widgets/game/cell_interactive.dart

lib/ui/widgets/game/game_board.dart

lib/ui/widgets/game/game_top_indicator.dart

lib/ui/widgets/game/select_color_bar.dart

lib/ui/widgets/global_app_bar.dart

lib/ui/widgets/helpers/header_app.dart

lib/ui/widgets/indicators/indicator_max_moves.dart

lib/ui/widgets/indicators/indicator_moves_count.dart

lib/ui/widgets/indicators/indicator_progress.dart