Create an Npm module and move PackageJson and Dependency there

[sodic]

I had this on my refactoring list. PackageJson is a part of the AppSpec but was in ExternalConfig, which means AppSpec depended on ExternalConfig.

On the other hand, Dependency was part of AppSpec, so ExternalConfig also depends on AppSpec

This PR introduces a new Npm module and fixes the circular dependency.

[Martinsos]

We can merge this one, right?

[sodic]

This file was completely unused.

Funnily enough, one module did use the printDep function but it defined it locally (didn't import this one) 😄

[Martinsos]

Nice, this is much better! Some small things, I commented on them.
Btw it would have helped in a PR like this with ton of files that have nothing but changes in the imports, if you said in the main comment that most of the changes are like that, and that you commented on specific files which are more interesting to look at. That would help me go fast through some files and focus on others, while now I had to focus on each one file not to miss anything, and still I almost missed some stuff because it all looks the same after Nth file hah.
EDIT: you did comment on some though, I am aware of that! Just I didn't know if you commented on all, so I had again to be very careful.

[sodic]

Btw it would have helped in a PR like this with ton of files that have nothing but changes in the imports, if you said in the main comment that most of the changes are like that

My bad, it used to be clear from the PR's name but then I changed it (for the worse it seems).