Make shell script output depend on log-level

[0xricksanchez]

There are two obvious ways to do so:

• Depending on the log level do a sed to (un-)set the -x flag in both rootfs.sh and debugger.sh. However, this requires rebuilding the containers for the changes to take effect. Additionally, we should implement a 'watcher' that only rebuilds the containers upon changes.
• Modify the entry point of both mentioned containers above and prepend a set -x. This does not require rebuilding and should work the same. However, this only seem to work for immediate commands, not a shell script, which is executed in another subshell itself... We would need to inherit the set options like so set -eu(x); . ./entrypoint.sh (argv). Doing that as an entrypoint in a container seems to not work out of the box... We probably need something like docker run .... <container> /bin/bash -c 'set -eu(x); source <entrypoint.sh>