chore: use packlist to write node_module ignores

[lukekarrys]

The gitignore file inside node_modules/ is now an allow list built
from the output of npm-packlist. This means that the only dependencies
that get checked in to source control are those that will end up in the
packed tarball, with the exception of some files that we always ignore.

This also moves the dependencies required to build the docs workspace
from devDependencies to dependencies so they are available for making
the docs after pruning. Ignoring these from source control was the
reason that the change to how we build the gitignore file was necessary.

[lukekarrys]

I started work on this originally using npm query so the results were all paths to directories which I then parsed into the gitignore format.

I just realized that now that this is using packlist, we could put the output of packlist directly into gitignore (filtered down to only paths that start with node_modules/), since packlist returns a list of individual files. The tradeoff would be a bigger gitignore file, but most of the complexity of the bundle-and-gitignore file would go away.

This is incorrect. In order to build an allow style list of nested paths in a gitignore file, you have to allow each previously ignored directory, so we'd still need most of what this file is doing.