Add goreleaser and Dockerfile

[cretz]

What was changed

• Add .goreleaser
• Add Dockerfile
• Add release workflow that invokes Goreleaser (will add Docker publishing later as we get closer to release)
• Add intentionally-very-minimal README

Everything else about releases is expected to remain the same in the nearterm (with other non-Brew package managers done separately as separate projects).

Known incompatibilities

No install shell script anymore, we will follow the likes of many other single-binary pieces of software and direct them to download, extract, and use (ideally supporting more package managers so the direct usage is less common).