Add to Node Core documention

[mhdawson]

Add to core documentation which covers 2 options for building your packages

• gyp
• cmake

Add to https://nodejs.org/dist/latest-v12.x/docs/api/addons.html#addons_building

Also talk about prebuild etc.?

[mhdawson]

Duplicate of #384

[jschlight]

It looks like the Building section on the proposed C++ Addons documentation page is part of a "Hello world" tutorial.

• Would it be better to create a new Building section on this page?

  https://nodejs.org/dist/latest-v12.x/docs/api/n-api.html

  It could go after Usage.

• Are there documentation guidelines for these pages? For example, linking to sites not maintained by the Node.js Foundation?

  I'm thinking this section should be at a "high-level" with links to the specific tools for the details.