Build ready to be used APKs in the CI
Currently, the APKs built in the CI are not ready to be deployed to production. We should do the following to change this:
- Change the way the version code is generated. We should maybe just use a build number server of some kind to generate monotonically increasing build numbers. For example, a pipeline step could be introduced which first generates the build numbers (in sequence!) for all targeted Android architectures and then update the Manifests.
- Add jobs in the CI which sign the APKs. This way, an APK can be fetched from the CI's artifacts and we can upload them as-is to Google Play and other platforms.