Suggestion: use init for intelmq container

[gethvi]

In case a bot crashes, the leftover process is usually reaped by the init system. However because there is no init system inside a container by default, there is a zombie process left behind which can cause trouble to intelmqctl (particularly the error "Commandline of the process N with commandline X could not be interpreted").

There is an option to have a simple init system inside the container which solves this issue:
https://docs.docker.com/engine/reference/run/#specify-an-init-process
https://docs.docker.com/compose/compose-file/#init