[🚧 WIP] Add `devcontainer` configuration

[ran-dall]

This adds the configuration for VSCode Devcontainer and Codespaces.

[changeset-bot[bot]]

🦋 Changeset detected

Latest commit: 5aaf4a7a431d36c2cc74c0b7dbe33b163208b30d

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 0 packages

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[ran-dall]

@natemoo-re Before this is ready, I think I want to get rid of nvm in favor of volta that you're already using.

[ran-dall]

@natemoo-re Restarting the work on this PR. So I replaced nvm with volta, but you still need to run volta install node && npm install --global pnpm to get everything set up. Maybe after https://github.com/volta-cli/volta/pull/1273, things will get nicer, but till then, I think this is as good as it's going to get.

Otherwise, it can be merged as-is, and I'll update it later when that PR is merged.

[ran-dall]

@natemoo-re Actually, I fixed it. Now it will automatically set up node and [email protected] with volta automatically. 🎉

So now it's 💯 ready for primetime.