Migrate to SDK 0.3.0 and fixes

- fix displaying list objects
- simplify `ListObjects`
- simplify `GetObjectHandler`
- simplify `HeadObjectHandler`
- add method for `GetBucketVersioningHandler`
- add method for `ListMultipartUploadsHandler`
- improvements for `HeadObjectHandler`, to display folders meta
- update dependencies
  - github.com/aws/aws-sdk-go v1.36.26
  - github.com/google/uuid v1.1.4
  - github.com/gorilla/mux v1.8.0
  - github.com/nspcc-dev/cdn-sdk v0.3.0
  - github.com/nspcc-dev/neofs-api-go v1.22.0
  - github.com/prometheus/client_golang v1.9.0
  - github.com/stretchr/testify v1.7.0
  - google.golang.org/grpc v1.35.0

Signed-off-by: Evgeniy Kulikov <kim@nspcc.ru>

api/handler/response.go

@@ -96,14 +96,14 @@ type CommonPrefix struct {
 type Object struct {
 	Key          string
 	LastModified string // time string of format "2006-01-02T15:04:05.000Z"
-	ETag         string
+	ETag         string `xml:"ETag,omitempty"`
 	Size         int64
 
 	// Owner of the object.
 	Owner Owner
 
 	// The class of storage used to store the object.
-	StorageClass string
+	StorageClass string `xml:"StorageClass,omitempty"`
 
 	// UserMetadata user-defined metadata
 	UserMetadata StringMap `xml:"UserMetadata,omitempty"`