fs: add cp method

[cappp]

Is your feature request related to a problem? Please describe.
Whenever I need to copy a directory to another destiny, I need to use an alternative library to do this.

Describe the solution you'd like
Add cp (Unix Name) method to fs, with the same utility of cp Unix, he can be like:

Parameters
src: PathLike
dest: PathLike
options: CpOptions

Describe alternatives you've considered
Library npc and fs-extra.

[iansu]

Thanks for the feature request! This is already being discussed by the Tooling Group (@nodejs/tooling).

The first step is producing an RFC that details exactly how the new cp method will work. Once we've completed that we'll be asking for input from the community. I'll share a link here when the RFC is ready so you and others can give your feedback.