fix(dev): lazily generate CSS bundle

[markdalgleish]

In order to improve build performance of Remix projects that aren't using CSS bundling features, this PR modifies the compiler so that the CSS bundle build (which is a separate esbuild compilation) isn't started until an import of @remix-run/css-bundle is detected in the client and server builds.

Since the cssBundleHref value is now entirely managed by an esbuild plugin, it's no longer part of the Remix manifest. This meant that the css-bundle package could be simplified. It no longer reads the manifest which means it doesn't depend on @remix-run/dev anymore, and it doesn't need to have different logic for client and server, so it can now be expressed in a single index.ts file.

[changeset-bot]

🦋 Changeset detected

Latest commit: 3a3da5a

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

This PR includes changesets to release 18 packages

Name	Type
@remix-run/css-bundle	Patch
@remix-run/dev	Patch
create-remix	Patch
remix	Patch
@remix-run/architect	Patch
@remix-run/cloudflare	Patch
@remix-run/cloudflare-pages	Patch
@remix-run/cloudflare-workers	Patch
@remix-run/deno	Patch
@remix-run/eslint-config	Patch
@remix-run/express	Patch
@remix-run/netlify	Patch
@remix-run/node	Patch
@remix-run/react	Patch
@remix-run/serve	Patch
@remix-run/server-runtime	Patch
@remix-run/testing	Patch
@remix-run/vercel	Patch

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[github-actions]

🤖 Hello there,

We just published version v0.0.0-nightly-a23338b-20230608 which includes this pull request. If you'd like to take it for a test run please try it out and let us know what you think!

Thanks!

[github-actions]

🤖 Hello there,

We just published version 1.17.1-pre.0 which includes this pull request. If you'd like to take it for a test run please try it out and let us know what you think!

Thanks!

[github-actions]

🤖 Hello there,

We just published version 1.17.1 which includes this pull request. If you'd like to take it for a test run please try it out and let us know what you think!

Thanks!