Added support for S3 storage classes (#28319)

* Added support for S3 storage classes

* Added missing translations for S3 storage class

* Changed default storage class values to preserve original behaviour

* Changed storage class description and example

* Fix translations ordering

* Change configuration defaults to empty strings

* Remove redundant empty string check

* Validate storage class variable against constants from S3 API docs

* Validate export storage class against constants

* Use slices for config validation

* Applied patch for translation ordering

api/v4/source/definitions.yaml

@@ -1429,6 +1429,8 @@ components:
               type: string
             AmazonS3SSL:
               type: boolean
+            AmazonS3StorageClass:
+              type: string
         EmailSettings:
           type: object
           properties:
@@ -1901,6 +1903,8 @@ components:
               type: boolean
             AmazonS3SSL:
               type: boolean
+            AmazonS3StorageClass:
+              type: string
         EmailSettings:
           type: object
           properties: