Draft: create core and dev images
This introduces the possibility to automatically create:
- Core images: the non strictly SFT specific part of the SFT containers (packages, hep-oslibs, basic settings ,...) Delimiter in Dockerfile: 'End Core' Image name: -core (e.g. centos8-core)
- Dev images: adds 'sudo' capability to sftnight on 'pro' images Delimiter in Dockerfile: 'Hook sudo' Image name: -dev (e.g. centos8-dev)
The patch also creates an archive area under builder and moves in there old settings.