add: basic Flutter app, not tested

app/.gitignore

app/.metadata

app/README.md

app/analysis_options.yaml

app/android/.gitignore

app/android/app/build.gradle

app/android/app/src/debug/AndroidManifest.xml

app/android/app/src/main/AndroidManifest.xml

...droid/app/src/main/kotlin/com/example/app/MainActivity.kt

...droid/app/src/main/res/drawable-v21/launch_background.xml

app/android/app/src/main/res/drawable/launch_background.xml

app/android/app/src/main/res/mipmap-hdpi/ic_launcher.png

app/android/app/src/main/res/mipmap-mdpi/ic_launcher.png

app/android/app/src/main/res/mipmap-xhdpi/ic_launcher.png

app/android/app/src/main/res/mipmap-xxhdpi/ic_launcher.png

app/android/app/src/main/res/mipmap-xxxhdpi/ic_launcher.png

app/android/app/src/main/res/values-night/styles.xml

app/android/app/src/main/res/values/styles.xml

app/android/app/src/profile/AndroidManifest.xml

app/android/build.gradle