Replace current test build with private docker images

Relate to #50 (closed)

This MR includes

• docker build files
• init docker README
• push build images to https://gitlab.cern.ch/snd-scifi/software/container_registry
• Factorise .gitlab-ci.yml

Remaining todo:

• Write a nicer README
• logging and json are standard python3 lib - no need to install - suggest to exclude these from the list to avoid confusion [https://gitlab.cern.ch/snd-scifi/software/-/blob/master/README.md#L35]. I will add autogen requirement in another MR, or should I do it here?.
• I can find only libusb but not libxxusb in https://pkgs.org/search/?q=libxxusb. Clarification needed.
• Change to ROOT 6.26/00 complied from source [without roofit mentioned in https://github.com/root-project/root/pull/10082]
• Change DAQ to ARM
• install python packages in build time
• [Move] Test cases - Move to another MR

@ezaffaro you may review and I think we can move the test cases to another MR.