WIP: initial support for Docker/Podman/OpenShift

This merge request introduces initial support for docker/podman and OpenShift support on the RAN side.

For the moment, we are able to build:

• plain docker under Ubuntu18 host
• plain docker/podman under a RHEL8 host
• using the build-config mechanism under OpenShift4.4

We were also able to deploy and test under Ubuntu18 host in plain docker:

• Connect from an eNB container to a USB- USRP B210 board
• Connect from an eNB container to a X300 USRP board

Initial benchmarking looks OK.

On a RHEL8 host with podman, we were not able to do the same. Still investigating.

There are still a lot to do:

• Fully automate the CMD and entrypoint on target images
• More bench-marking
• Documentation