Add docker support

[mamueluth]

working: Building an creating of docker workspace works so far.

issues: Auto startup is missing. (Need to adjust source path and setup script) When sourcing rtw in docker and no rolling is present-> error is thrown, have to look into it. Possibly hardcoded

Maybe optional: May management of docker images/containers would be nice.

[destogl]

Some notes after testing this:

• [x] when I now open a new terminal, I get asked about not set default ROS version. I think we talked about this, but what I don't like is that I have to actively press a key.
• [x] write in a nice color before code is executed in docker, e.g., line in blue (use TERMINAL_COLOR_*) "The following output is from command executed in Docker container."
• [x] I think that docker container was tried to be created twice also it seems that invalid name for the container (but have no idea why was defined).
• [x] When using base workspace folder in form folder/subfolder the mapping in docker is not correct. Why? (I am now mapping the full workspace path)
• [x] When users enters into docker it should end in his home directory and not root dir ("/") --> this causes that the workspace is not build properly (see also review comment below)
• [x] map $HOME/.ssh per default into docker
• [x] for mounting folder prefix and suffix has to be considered. Otherwise, the whole workspace is mounted into docker. This is not what we want because there is a danger to “contaminate” other workspaces from incompatible docker container.
• [ ] Recognize if we are in docker or not and if not and workspace is using docker we should not execute source .../setup.bash (this is important later to support non-ros compatible OSes)
• [x] will docker container start properly after host system is restarted? I guess we should execute docker run again in that case.
• [x] when sourcing workspace that is using docker on host, notify user about that.

[mergify[bot]]

This pull request is in conflict. Could you fix it @mamueluth?