Handle SIGINT signals in Nuxeo Docker Image

When running the Nuxeo Docker Image with -ti option we're unable to stop the container by pressing ctrl+c, which sends a SIGINT signal to the process.

This looks like a Docker PID 1 issue, the main process is nuxeoctl, a bash script, which doesn't handle signals when it is PID 1.

We want to be able to ctrl+c our Nuxeo container.