Use dumb-init in docker images

Why

https://blog.phusion.nl/2015/01/20/docker-and-the-pid-1-zombie-reaping-problem/

https://petermalmgren.com/signal-handling-docker/

https://medium.com/@BeNitinAgarwal/an-init-system-inside-the-docker-container-3821ee233f4b#:~:text=The%20init%20process%20is%20responsible,for%20the%20top%2Dmost%20process.

Solution

 https://github.com/Yelp/dumb-init