chore(oas): replace requestBody with $ref to req class JSDoc OAS (#2867)

### What

Move inline OAS requestBody schema declaration under their respective class-validator classes in order to expose them through  `#/components/schemas`. Replace inline OAS requestBody schema with a `$ref` reference pointing to the newly declared schema.

### Why

Having requestBody declared as its own "named" schema will allow OAS code generators to output typed entities/DTO that can be manipulate without having to reference the route/operation.

### How

Declare a new @schema JSDoc for each class-validator used to parse and validate request body. Move the current inline requestBody to the new @schema.

### Test

- Ran OAS validator.
- Ran docs build script.

Expect no visible changes to the documentation.

### Out-of-scope

requestBody of type `multipart/form-data` used for file uploads. These will be address as part of CORE-934
- [create-upload.ts](https://github.com/medusajs/medusa/blob/58d23a7b45b6dde8bdeed0bb268139a0017f1649/packages/medusa/src/api/routes/admin/uploads/create-upload.ts#L87-L90)
- [create-protected-upload.ts](https://github.com/medusajs/medusa/blob/58d23a7b45b6dde8bdeed0bb268139a0017f1649/packages/medusa/src/api/routes/admin/uploads/create-protected-upload.ts#L87-L90)

Path Parameter and Query Parameter. These will need more research and experimentation, part of CORE-931

---

Resolves CORE-853

packages/medusa/src/api/routes/admin/notes/create-note.ts

@@ -14,21 +14,7 @@ import { EntityManager } from "typeorm"
  *  content:
  *    application/json:
  *      schema:
- *        type: object
- *        required:
- *          - resource_id
- *          - resource_type
- *          - value
- *        properties:
- *          resource_id:
- *            type: string
- *            description: The ID of the resource which the Note relates to.
- *          resource_type:
- *            type: string
- *            description: The type of resource which the Note relates to.
- *          value:
- *            type: string
- *            description: The content of the Note to create.
+ *        $ref: "#/components/schemas/AdminPostNotesReq"
  * x-codeSamples:
  *   - lang: JavaScript
  *     label: JS Client
@@ -104,6 +90,24 @@ export default async (req, res) => {
   res.status(200).json({ note: result })
 }
 
+/**
+ * @schema AdminPostNotesReq
+ * type: object
+ * required:
+ *   - resource_id
+ *   - resource_type
+ *   - value
+ * properties:
+ *   resource_id:
+ *     type: string
+ *     description: The ID of the resource which the Note relates to.
+ *   resource_type:
+ *     type: string
+ *     description: The type of resource which the Note relates to.
+ *   value:
+ *     type: string
+ *     description: The content of the Note to create.
+ */
 export class AdminPostNotesReq {
   @IsString()
   @IsNotEmpty()