combine,compress,crypt,hasher,union: support wrapping backends with PartialUploads

This means that, for example, wrapping a sftp backend with crypt will
upload to a temporary name and then rename unless disabled with
--inplace.

See: https://forum.rclone.org/t/backup-versioning/38978/7

backend/hasher/hasher.go

@@ -166,6 +166,7 @@ func NewFs(ctx context.Context, fsname, rpath string, cmap configmap.Mapper) (fs
 		ReadMetadata:            true,
 		WriteMetadata:           true,
 		UserMetadata:            true,
+		PartialUploads:          true,
 	}
 	f.features = stubFeatures.Fill(ctx, f).Mask(ctx, f.Fs).WrapsFs(f, f.Fs)