gitlab-ci: Fix x86_build docker image build, and split it up
Using the wine-development
packages from Debian buster removes the need for using packages from Debian testing, which fixes the x86_build
docker image build.
Take this opportunity to split up the x86_build
image similarly as was previously done with x86_test
, which should be more efficient in terms of storage & network bandwidth when changes are made to the images.