Add convenience packages

Since we changed our environments to more or less work only in the volumes, the need of starting a shell inside the container and working has increased.

This MR adds some packages should bring a better experience when working inside the containers or when interacting with those.

• Add pvhttps://wiki.ubuntuusers.de/pv/
  Using pv, we can show a progress bar whenever we pipe something. This is very usefull when importing/exporting/moving (etc) large data (i.e. databases, files, similar). It works like cat but allows showing the progress
• Add htophttps://wiki.ubuntuusers.de/htop/