Group CLI options for easier navigation

[MaxDesiatov]

Currently, all of the options available in the driver are listed in a flat namespace with no logical grouping. It's hard to navigate these options both in the source code and when looking through these options in --help output. It would be great if options were presented in groups.

[natikgadzhi]

👋 I just started reading in, but that's my absolute first time touching anything around swift-driver. Might ask for some hand-holding.

I'm diving in the driver docs.

Would a good approach be to tweak makeOptions.cpp, or should we group them after they're already generated into Options.swift?