Make hh --help agent-friendly and human-friendly: 70 fewer flags

Summary:
## What

`hh --help` now has succinct output, with 70 fewer flags.

To see all options, the dev-or-agent can do `--ultrahelp`

Also, we now test `--help` so we can control its evolution and avoid regressions.

## Why

hh_client --help was very noisy, which I suspect could confuse
agents and developers.

It's just not generally a good experience to have a wall of rarely-used options.

At the same time, I wanted options used by Hack team and our partner teams to still be available, so followed enetsee's suggestion of sticking the rest in --utlrahelp.

Reviewed By: madgen

Differential Revision: D94911047

fbshipit-source-id: e2b247cbf9bfe0d65ae39740d5c1b4b8573e8421

Author: mheiber