Support multiarchitecture images in Docker

[aarroyoc]

Currently Docker supports multiarchitecture images, where the appropiate image for the architecture is chosen at runtime (https://developer.ibm.com/linuxonpower/2017/07/27/create-multi-architecture-docker-image/).

I found out that in Raspberry Pi just using this:

docker pull swipl:8.16

downloads the amd64 image instead of the arm32v7 image. However, Docker supports multiple architectures by combining manifests, so that command will download the arm32v7 image on my Raspberry.

[ninjarobot]

The docker official images support them slightly differently, but we are building for both arm architectures.

[aarroyoc]

Yes, I know that the image arm32v7/swipl:8.16 image exists but, it forces me to use two different Dockerfiles when I try to use it on desktop and on Raspberry. It's already possible to use the same name to do multiarchitecture (for example, alpine or nginx will just select the correct architecture at runtime)