* Simplify creating an AppImage
- package.sh packages the build result into an AppImage. It requires
squashfs-tools to work
- runtime-x86_64 is a binary distributed by the AppImage project that takes
care of extracting and running the image
* use AppRun from AppImage project
* clean up no longer needed bits
* Keep docker way of working around
- Docker now also uses `package.sh`, so no more need for FUSE.
- Fetch binaries instead of storing in git.
* Fix details
* wait a little longer for the container to start
