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/combine/combine.go

@@ -233,6 +233,7 @@ func NewFs(ctx context.Context, name, root string, m configmap.Mapper) (outFs fs
 		ReadMetadata:            true,
 		WriteMetadata:           true,
 		UserMetadata:            true,
+		PartialUploads:          true,
 	}).Fill(ctx, f)
 	canMove := true
 	for _, u := range f.upstreams {

backend/compress/compress.go

@@ -186,6 +186,7 @@ func NewFs(ctx context.Context, name, rpath string, m configmap.Mapper) (fs.Fs,
 		ReadMetadata:            true,
 		WriteMetadata:           true,
 		UserMetadata:            true,
+		PartialUploads:          true,
 	}).Fill(ctx, f).Mask(ctx, wrappedFs).WrapsFs(f, wrappedFs)
 	// We support reading MIME types no matter the wrapped fs
 	f.features.ReadMimeType = true

backend/crypt/crypt.go

@@ -268,6 +268,7 @@ func NewFs(ctx context.Context, name, rpath string, m configmap.Mapper) (fs.Fs,
 		ReadMetadata:            true,
 		WriteMetadata:           true,
 		UserMetadata:            true,
+		PartialUploads:          true,
 	}).Fill(ctx, f).Mask(ctx, wrappedFs).WrapsFs(f, wrappedFs)
 
 	return f, err

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)
 

backend/union/union.go

@@ -902,6 +902,7 @@ func NewFs(ctx context.Context, name, root string, m configmap.Mapper) (fs.Fs, e
 		ReadMetadata:            true,
 		WriteMetadata:           true,
 		UserMetadata:            true,
+		PartialUploads:          true,
 	}).Fill(ctx, f)
 	canMove, slowHash := true, false
 	for _, f := range upstreams {