Add feedback capabilities to SG

Created by: jhchabran

As an engineer, I can immediately provide feedback on any command of command group of sg.

It could look like:

sg ci --feedback
sg run redis-postgres --feedback
sg ... --feedback

And it would take you to https://github.com/sourcegraph/sourcegraph/discussions/categories/developer-experience to create a new thread or possibly point you to an existing one.

Another possibility is to have

sg feedback anything you want here 

and send you to that exact place.

In any of those scenario, we could package along the way a bunch of metadata (sg doctor output? sg version ... ?)