feat!: type auto-generation (#6657)

Types are now auto-generated by default.

You can opt-out of this behavior by setting:
```ts
buildConfig({
  // Rest of config
  typescript: {
    autoGenerate: false
  },
})
```

test/email/config.ts

@@ -48,4 +48,7 @@ export default buildConfigWithDefaults({
       file: imageFile,
     })
   },
+  typescript: {
+    outputFile: path.resolve(dirname, 'payload-types.ts'),
+  },
 })

test/email/payload-types.ts

@@ -49,6 +49,8 @@ export interface Media {
   filesize?: number | null;
   width?: number | null;
   height?: number | null;
+  focalX?: number | null;
+  focalY?: number | null;
   sizes?: {
     thumbnail?: {
       url?: string | null;