Add globalImport

[graup]

Based on the discussion at #600

The rule format mirrors the CSS spec: https://developer.mozilla.org/en-US/docs/Web/CSS/@import

[changeset-bot]

🦋 Changeset detected

Latest commit: 1bfb96a

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

This PR includes changesets to release 8 packages

Name	Type
@vanilla-extract/css	Minor
@fixtures/features	Patch
@fixtures/low-level	Patch
@fixtures/recipes	Patch
@fixtures/sprinkles	Patch
@fixtures/themed	Patch
@fixtures/unused-modules	Patch
vanilla-extract-example-webpack-react	Patch

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[mattcompiles]

Couple of concerns with adding an @import API:

• You can use it to import other local CSS files which most bundlers will try to interpret. This leads to scenarios that will break as relative imports will not work currently. If we merge Use realistic file paths in file scopes #647 this scenario may be able to be improved but not sure it'd ever be a good idea anyway.
• In what scenario is using CSS import an ideal solution? As mentioned in the linked discussion, using CSS import leads to request waterfalls. Why wouldn't I just add the assets directly to the HTML?

[graup]

• Yeah I'm also a bit concerned about local imports. That's a can of worms we likely don't want to open.
• If you link to the woff2 files directly, I believe that has a couple disadvantages: I suspect Google is doing some magic to only deliver the file types needed for the user's browser. Also if they ever update the rules or move the files, you'll miss out on that.

The better workaround is importing the CSS using a <link> tag. That is fine, we just have to tell our consumers to do that.

So yeah, this is not a must-have feature.

[graup]

Since there hasn't been additional interest in this feature, I'm gonna close my PR!

[SalahAdDin]

It would be a great feature man @graup !