Implement shutil in Node.js core

Based on a discussion in the Tooling WG meeting on March 19, 2019 we've decided that the best way forward with rimraf is to implement a new module in Node.js core inspired by shutil from Python: https://docs.python.org/2/library/shutil.html#module-shutil

Eventually we'd like to implement more methods from this module. I've volunteered to do the initial implementation of rimraf.