FR: metadata for fdroid

[mueller-ma]

When providing metadata via a fastlane directory, fdroid automaticly shows them in the store. You dont need to install fastlane, just create the folder

Example: https://github.com/Freeyourgadget/Gadgetbridge/tree/master/fastlane/metadata/android/en-US
Info: https://github.com/fastlane/fastlane/blob/2.28.7/supply/README.md#images-and-screenshots