Write binding.gyp files from a JavaScript build script

[MRayermannMSFT]

Initial thoughts:

1. Have a .js file in build-common which has "write a build binding.gyp file" and "write a prod binding.gyp file" APIs
2. Have the APIs automatically:
   • Detect if package uses nan or node-addon-api and then fill out the correct "include_dirs"
   • Find all Windows/macOS/Linux source files (standardize the _win32/_macos/_linux) file suffix?) and fill out "sources" for the various "conditions" on the target
   • Determine "target_name" from whatever .d.ts file exists at package root