feat: filename compound index (#7651)

Allow a compound index to be used for upload collections via a
`filenameCompoundIndex` field. Previously, `filename` was always treated
as unique.

Usage:

```ts
{
  slug: 'upload-field',
   upload: {
     // Slugs to include in compound index
     filenameCompoundIndex: ['filename', 'alt'],
  },
}
```

scripts/pack-all-to-dest.ts

@@ -59,7 +59,7 @@ async function main() {
 ${chalk.white.bold(filtered.map((p) => p.name).join('\n'))}
 `)
 
-  //execSync('pnpm build:all --output-logs=errors-only', { stdio: 'inherit' })
+  execSync('pnpm build:all --output-logs=errors-only', { stdio: 'inherit' })
 
   header(`\n 📦 Packing all packages to ${dest}...`)