update: move pictures, remove initial flutter code

app/ios/Runner/Base.lproj/Main.storyboard

app/ios/Runner/Info.plist

app/ios/Runner/Runner-Bridging-Header.h

app/ios/RunnerTests/RunnerTests.swift

app/l10n.yaml

app/lib/main.dart

app/lib/src/app.dart

app/lib/src/localization/app_en.arb

app/lib/src/sample_feature/sample_item.dart

app/lib/src/sample_feature/sample_item_details_view.dart

app/lib/src/sample_feature/sample_item_list_view.dart

app/lib/src/settings/settings_controller.dart

app/lib/src/settings/settings_service.dart

app/lib/src/settings/settings_view.dart

app/linux/.gitignore

app/linux/CMakeLists.txt

app/linux/flutter/CMakeLists.txt

app/linux/flutter/generated_plugin_registrant.cc

app/linux/flutter/generated_plugin_registrant.h

app/linux/flutter/generated_plugins.cmake