[webpack-resolver]: use enhanced-resolve?

[benmosher]

Current version of the Webpack resolver is a hand-rolled minimum-viable-product that satisfied my initial needs, but given #181, #165, #135, #134, #164, seems like it would be better to integrate more directly with Webpack's internals, to avoid drift.

Need to

• investigate how feasible this is. (I looked briefly before, seemed fairly involved)
• find necessary pieces by locating a sibling webpack package and then interacting with its dependencies from there (to avoid installing a parallel, incompatible version of enhanced-resolve, etc)
• version the resolver in some way matching the version of Webpack with which it was developed/verifed?

[benmosher]

This was shipped with Webpack resolver version 0.3.0, IIRC. compatible with only Webpack v1 ATM