Convert local setup to a runner

[wesleytodd]

Took a quick look at converting @RafaelGSS's local server/client into a runner. I didn't have time this morning to look at the wrk2/autocannon stuff, but can assuming that #62 was not trying to say "ditch that abstraction entirely", which maybe it is and then I would like to discuss why we should do that.

[wesleytodd]

There are still quite a few gaps:

• Sorting out local installs for the CLI's (global installs are a no go imo)
• Finding the right format for passing requests to wrk2 like we do to autocannon
• Applying overrides
• Decide how we would want to support the --node option (maybe this one doesn't since it would use what node you have locally)

But @RafaelGSS are you alright with this direction so that we align with the other runner styles and features?

[RafaelGSS]

Sorry delay, @wesleytodd, a lot of things are going on recently, as you might know.

To be honest, I was trying to say "ditch that abstraction entirely" - It's a personal preference, so I'm fine leaving it as internal packages. My feeling that this increases the contribution barrier and makes things overly complex.

Also, I do believe Wrk2 (at least) should be a global binary - making it available through this CLI will make things very complex as the binary needs different dependencies according to each supported environment. Leaving that open for the "sysadmin" seems a better choice to not make things more complex than it is nowadays.

(That's what we do for Node.js too)