Nomia README refresh

[ddbeck]

This is the companion to scarf-sh/scarf#22. Like that issue, I used ddbeck/readme-checklist to guide me to a list of proposed changes. I'm putting together the first companion PR to begin addressing some of these things, too.

Overall, the aim here is to help readers figure out what Nomia is, evaluate it, and get sucked into participating. 🚀

(I'm going to follow this up with a PR that begins to address some of this.)

Identify

• Link to repo/homepage from Nomia heading
• Say something about authorship (e.g., "By the Scarf team and contributors")

Evaluate/engage

This function of the README is a bit tricky. Ordinarily, evaluate and engage are two separate goals. But Nomia's not at the point where it can address a pain that developers have, so it's tough to do the typical "Nomia helps you…" introduction. Instead, we're trying to pique interest in what Nomia will someday be, to get more people involved

• Give readers the elevator pitch length version of "What is Nomia?"

  My initial attempt looks something like this:

  Nomia is inspired by tools such as Nix, Unison, and Git. They all provide distinct, immutable names for resources like packages, code, and files. Nomia wants to bring them together (and more!) to make reproducing whole environments—from your editor to code to data to complete running services—as easy as git switch.

• Break software description out to an additional file with richer detail (e.g., incorporating #11)

• Make it explicit that Nomia is a new project that wants participation

• Add a distinct call-to-action (e.g., Join us on Discord or attend a pairing session)

Use

This is a bit abstract and subject to change, so I recommend skipping over this for now.