Use and apply flutter lints

analysis_options.yaml

android/gradle.properties

lib/config/menu.dart

lib/cubit/api_cubit.dart

lib/cubit/api_state.dart

lib/cubit/settings_cubit.dart

lib/main.dart

lib/models/api_data.dart

lib/models/game/game.dart

lib/models/game/game_board.dart

lib/models/game/game_cell.dart

lib/models/game/game_settings.dart

lib/models/interface_type.dart

lib/network/api.dart

lib/repository/api.dart

lib/ui/painters/cell_painter.dart

lib/ui/painters/graph_painter.dart

lib/ui/screens/about_page.dart

lib/ui/screens/api_page.dart

lib/ui/screens/camera_page.dart