SPI-2251: 101 build dev5 aarch64 in docker

This changes the aarch64 builds to run on the new arm virtual machine using docker.

This also adds a new axis to the build matrix to define the architecture x86 vs arm, because we need to use the label for the OS so that we can also build on centos9. Not sure this axis is working 100% of the time, or if other pipeline configs interfere. Building manually was successful after some more tweaks to the docker image (see sft/docker)

PS: had to edit the properties.txt file to pass HOST_ARCH to the pipeline build.