Improve app metadata, include fdroid metadata in repository

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

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

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

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

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

android/gradle.properties

assets/icons/button_back.png

assets/icons/button_shuffle.png

assets/icons/difficulty_3x3.png

assets/icons/difficulty_4x4.png

assets/icons/difficulty_5x5.png

assets/icons/game_win.png

fastlane/metadata/android/en-US/changelogs/42.txt

fastlane/metadata/android/en-US/images/featureGraphic.png

fastlane/metadata/android/en-US/images/icon.png

fastlane/metadata/android/fr-FR/changelogs/42.txt

fdroid_metadata.yml

icons/build_application_icons.sh

icons/build_game_icons.sh

icons/featureGraphic.svg