Docker & oracle-rdbms-server-12cR1-preinstall

There is an extremely annoying  behavior of oracle-rdbms-server-12cR1-preinstall, when you want to use it in conjunction with docker images like breed85 or oraclelinux: this official package of Oracle's blocks every attempt to switch to the user oracle (su - oracle), which one is forced to do, when he wants to install Oracle SW and create Oracle databases in a Docker container. I have written 2 posts in July about that and none of them was correct. After 2 months I was forced to come back in order to accomplish our Dockerproject . Here is, what I have found out.