replace yargs with commander

[kaievns]

yargs seems pretty good, but commander is so much better.

it has a nice and clean declarative API for the CLIs, it automatically builds great help pages, supports sub-commands, handles input validation and so on. and it's a goto tool for many devs when they want to build a CLI in node

[nwinch]

Yep, looks good. yargs seems to be working fine ATM, so let's mark this as low until it might be something we need.