This is mostly for those cases where Dockerfile RUN instructions do not run `remove-apt-lists`, either by accident or on purpose.
This might speed up `apt-get update` depending on environment settings and availability of translations.
This integrates a custom script into the APT configuration. That same script is also run during the bootstrap. A second custom script takes care of the integration and removes itself when done. Complements 13f84159.
13f84159
Olaf Meeuwissen