Revert "Add python and gcc to the Dockerfiles."
Revert "Add python and gcc to the Dockerfiles."

This reverts commit 803f45437f7f293fecebc5d00e766164131eaf4c.

We're not installing zanata-js by default anymore and are not pulling
translations on every build.

weldr/welder-web,jkozol/welder-web,jkozol/welder-web,weldr/welder-web,weldr/welder-web,jkozol/welder-web,jkozol/welder-web,weldr/welder-web