Publish APK in F-Droid and enable deterministic builds

Currently, no APK is published over F-Droid which is another alternative store for Android.

Furthermore, it would be vital to provide a way to reproduce official builds and enable deterministic builds so that we can trust the provided binaries.

As far as I see it, StopCovid is trusting Google's app signing mechanism, which means that Google holds your signing key, right?

For a governement-backed application, it would be a shame to not, at least, provide a non-Google alternative on a store such as F-Droid. Even more when you would be able to offer reproductible builds and a transparency binary log.