Don't make persistent changes to the build environment in jobs

Several jobs make persistent changes to the build environment, e.g. https://github.com/openmicroscopy/devspace/blob/0.10.0/home/jobs/BIOFORMATS-push/config.xml#L78 which installs scc outside of a sandboxed virtualenv.
Either these dependencies should be in the Dockerfile, or in a dedicated virtualenv. Moving all builds to docker would also solve this problem.