rce-tool to list info

[dominiquehunziker]

Add a script/tool to list info from config file, eg

1. Where is container filesystem (maybe so more useful info regarding the filesystem?)
2. Which package paths are mounted in the container
3. Gather a list of ROS packages available in the container (based on the package paths mounted in the container)
4. print a list of users in the cred db

Maybe add a feature to fetch all log files to simplify bug reports (and any other info we usually need)? (This implies that the logs are no longer printed to stdout, but to an actual logfile...)

anything else?