build: relocate site netlify.toml to site/ directory

[ndhoule]

This change moves the site netlify.toml to the site/ directory.

Previously, the site-build workflow went like this:

• Netlify Build executed npm install at the root of the project (by default)
• After package installation, the postinstall hook triggered a CLI build
• Netlify Build would execute netlify.toml#build.command, which:
  • Entered the docs directory
  • Ran npm install against docs/package.json
  • Ran a site build (which implicitly relied on the root directory npm install and npm run build steps)

To make this change, I modified the logic to:

• Netlify Build starts in the site/ directory and executes npm install
• site/netlify.toml#build.command enters the root and preps the CLI, then returns to the docs/ directory
• We then build the site

In this way, the site's dependency on the CLI's source is more clear--we assume nothing about the state of the root directory before building the docs site.

Some other noteworthy changes here:

• While making these changes, I realized the (JavaScript) site build scripts assume that the CLI has been built to the dist directory. I modified them to be transpiled at runtime and to import from src.
  • I'm not particularly attached to this change, but it reduces the amount of setup steps required and will let us convert these scripts to TypeScript.
• I moved the site functions to the standard Netlify functions location, site/netlify/functions. Doing so also let me move a dependency that was only used on the site (@bugsnag/js) out of the root, which slims the CLI's dependency tree.
• I got rid of most of the site: tasks from the top-level package.json. (I left the docs task, though.)
• These changes require that we change the CLI site's base directory to docs. The site is refusing to build on main right now anyway, so I already made that change.

[github-actions]

📊 Benchmark results

Comparing with 25fcdd8

• Dependency count: 1,182 ⬇️ 0.34% decrease vs. 25fcdd8
• Package size: 281 MB ⬇️ 0.42% decrease vs. 25fcdd8
• Number of ts-expect-error directives: 724 (no change)

[jmarlena]

@ndhoule Assuming the docs CLI site still builds fine with these changes, this is fine to merge! If it's hard to test the site build, we can always merge this and prepare to revert if needed.

[ndhoule]

@jmarlena Thanks! This is testable (pre-merge) by visiting the deploy preview:

https://deploy-preview-7090--cli.netlify.com/

I did a spot check on a few of the pages by flipping back and forth between the preview and cli.netlify.app and didn't notice any difference.