Turbopack: Support data URI sources (#76865)
These are technically not entirely spec compliant as identical data urls in different folders aren't deduplicated (but each generate a new module). But this is good enough for now.
You can now do
```js
import { bar } from "data:text/javascript,export var bar = 1234;";
import data from 'data:application/json,{ "foo": 1234 }';
import dataURLEncoded from 'data:application/json,%7B%20%22foo%22%3A%201234%20%7D';
import dataBase64Encoded from 'data:application/json;base64,eyAiZm9vIjogMTIzNCB9';
import "data:text/css,body { color: red }";
it("support data URL imports", () => {
expect(bar).toEqual(1234);
expect(data).toEqual({ foo: 1234 });
expect(dataURLEncoded).toEqual({ foo: 1234 });
expect(dataBase64Encoded).toEqual({ foo: 1234 });
});
```
Only data-urls in JS ESM imports are turned into modules. For JS, turning data-urls into separate modules is zero-cost, because they all end up in the same bundle anyway, but that is not the case for image data urls in CSS.
