support/docker: sort the list of installed packages

As suggested in the docker best practices [0], order the package list
alphabetically, and list only one package per line.

This will be much usefull later, we need to update the list of installed
packages, like adding new ones for example.

[0] https://docs.docker.com/develop/develop-images/dockerfile_best-practices/#sort-multi-line-arguments



Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Ricardo Martincoski <ricardo.martincoski@gmail.com>
Reviewed-by: Ricardo Martincoski <ricardo.martincoski@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>