Remove contradictory analogy

[bdevans]

I propose removing this initial comparison of Dockerfiles with Makefiles because:

1. It is inconsistent with the main analogy (see figure) where a Dockerfile is compared to source code
2. We later recommend including a Makefile in your repository to help remember arguments for commands

As such, this comparison might cause unnecessary confusion. I also think the sentence reads better without this clause.

[vsoch]

Didn’t it already get resubmit?

[bdevans]

Ah, well if it's too late, then it's too late! 🤷‍♂️ If not, I think it would be a useful edit. I'll stop looking at it now anyway 😄

[nuest]

Well, if we get the text back once more, we can include it. None of the reviewers complained about this though, and unsolicited changes might have caused more trouble than benefit :shrug: .

[nuest]

Unsolicited changes will indeed not work in our favour, so let's leave it in and see what the readers have to say.