Updates the image to have a newer build environment, which is required
for some of the maintainer scripts.
Increases the image size from 414 to 545 MB.
Using `make container` or, if you don't have automake/gmake on your host
system, `./scripts/container.sh` will build an image for the current
branch your are on and drop you into a shell running inside a container
using that image.
From there all tooling required to work on Gluon is available.
Supports both podman (preferred) and docker.