e8dd3389a7
Update the android build docker image: - rebase on ubuntu 22.04; - add tooling required to sign APKs; - changes to make the container re-usable; - change to a multi-stage build to keep the image size smaller; - generic improvements to the Dockerfile Also update the example script for how to use the container. Signed-off-by: Michael Keller <github@ike.ch>