Remove explicit dependency on node-gyp

[winstliu]

Requirements

• Filling out the template is required. Any pull request that does not include enough information to be reviewed in a timely manner may be closed at the maintainers' discretion.
• All new code requires tests to ensure against regressions

Description of the Change

This dependency was added in #730 as a way to always know how to access the node-gyp binary. However, npm has been bumped several times since then without touching node-gyp, leaving it quite outdated. I believe it should be fine to remove this dependency and simply rely on the version npm ships with.

Alternate Designs

Update it to the version npm ships with.

Benefits

Less packages to maintain. This should also unblock using Visual Studio 2017 build tools.

Possible Drawbacks

npm's directory flattening scheme may change, which will require us to update the node-gyp search path. I think if it does change, we'll notice it fairly quickly and be able to change the path without too much hassle.

Verification Process

None yet.

Applicable Issues

None.

[lee-dohm]

Can you publish a pre-release version of apm and open a PR on Atom to use that new version in order to confirm that we get a green build? Contact me in Slack if you have any questions.

[vinkla]

@50Wliu could this pull request solve atom/atom#18540?

[winstliu]

Perhaps? I don't really know; apm's internals are quite complicated and I'm still figuring out how things work and why they were designed this way.

[winstliu]

Some of these changes weren't the cleanest, specifically all the node-gyp path updating. I'm wondering if we should just try updating our version of node-gyp rather than depending on npm's.

[rafeca]

Thanks for doing this! Since the PR on atom/atom using the prerelease version passes, I'm confident about merging it.

@50Wliu can you take care of publishing a stable release afterwards and updating the atom/atom PR to point to the stable release?