Php: Install `apt-utils` in Debian images

[mcnesium]

In every build the noisy warning debconf: delaying package configuration, since apt-utils is not installed scrolls by. people state, it should be installed, though, so what about adding it to the apt-get update commands?

[tianon]

This is a harmless warning, and the aforementioned utility (apt-extracttemplates) is _only_ used for interactive question-answering, which is never used during docker build (since our apt-get install is not attached to a TTY, so we simply get the default answer to all questions).

Is there anything that adding this package to our image do for us besides removing this already-harmless warning and slightly increasing the size of the overall image?

[mcnesium]

Removing harmless but noisy warnings is good imho, because it makes real warnings stick out better. I don't know if there are any more benefits beside this, it was just a suggestion. If drawbacks outbalance, nevermind this.

[tianon]

I think the drawback of installing packages we don't actually _need_ is strong enough to warrant avoiding this. Nothing stopping you from installing this in your own images based on these to remove the warnings from your own builds, though! :heart:

Sorry!