config: replace use_write_cache with writecache.enabled

This is the way things are done with `grpc.tls` and in neo-go.

Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>

cmd/neofs-node/config/engine/config_test.go

@@ -55,7 +55,7 @@ func TestEngineSection(t *testing.T) {
 
 			switch num {
 			case 0:
-				require.Equal(t, false, sc.UseWriteCache())
+				require.Equal(t, false, wc.Enabled())
 
 				require.Equal(t, "tmp/0/cache", wc.Path())
 				require.EqualValues(t, 2147483648, wc.MemSize())
@@ -85,7 +85,7 @@ func TestEngineSection(t *testing.T) {
 				require.Equal(t, false, sc.RefillMetabase())
 				require.Equal(t, shard.ModeReadOnly, sc.Mode())
 			case 1:
-				require.Equal(t, true, sc.UseWriteCache())
+				require.Equal(t, true, wc.Enabled())
 
 				require.Equal(t, "tmp/1/cache", wc.Path())
 				require.EqualValues(t, 2147483648, wc.MemSize())

cmd/neofs-node/config/engine/shard/config.go

@@ -20,16 +20,6 @@ func From(c *config.Config) *Config {
 	return (*Config)(c)
 }
 
-// UseWriteCache returns value of "use_write_cache" config parameter.
-//
-// Panics if value is not a valid bool.
-func (x *Config) UseWriteCache() bool {
-	return config.Bool(
-		(*config.Config)(x),
-		"use_write_cache",
-	)
-}
-
 // BlobStor returns "blobstor" subsection as a blobstorconfig.Config.
 func (x *Config) BlobStor() *blobstorconfig.Config {
 	return blobstorconfig.From(

cmd/neofs-node/config/engine/shard/writecache/config.go

@@ -31,6 +31,13 @@ func From(c *config.Config) *Config {
 	return (*Config)(c)
 }
 
+// Enabled returns true if write-cache is enabled and false otherwise.
+//
+// Panics if value is not a boolean.
+func (x *Config) Enabled() bool {
+	return config.Bool((*config.Config)(x), "enabled")
+}
+
 // Path returns value of "path" config parameter.
 //
 // Panics if value is not a non-empty string.