fix!: improve collection / global slugs type-safety in various places (#8311)

**BREAKING:**
Improves type-safety of collection / global slugs by using `CollectionSlug` / `UploadCollectionSlug` and `GlobalSlug` types instead of `string` in these places:
Adds `UploadCollectionSlug` and `TypedUploadCollection` utility types

This also changes how we suggest to add an upload collection to a cloud-storage adapter:
Before:
```ts
azureStorage({
  collections: {
    [Media.slug]: true,
  },
}) 
``` 

After:
```ts
azureStorage({
  collections: {
    media: true,
  },
}) 
```

packages/plugin-nested-docs/src/types.ts

@@ -1,3 +1,5 @@
+import type { CollectionSlug } from 'payload'
+
 export type Breadcrumb = {
   doc: string
   label: string
@@ -22,7 +24,7 @@ export type NestedDocsPluginConfig = {
   /**
    * The slugs of the collections this plugin should extend. If you need different configs for different collections, this plugin can be added to your config more than once having different collections.
    */
-  collections: string[]
+  collections: CollectionSlug[]
   generateLabel?: GenerateLabel
   generateURL?: GenerateURL
   /**