[#1008] ir/container: Customize fee for named container registration

In notary disabled environment, approval of container creation with nice
name attribute takes much more additional GAS than other operations
(due to NNS invocation).

Morph library changes:
  * add the ability to specify per-op fees using `StaticClient` options;
  * add the ability to customize fee for `Put` operation with named
    container in container morph client.

Inner Ring changes:
  * add `fee.named_container_register` config value which specifies
    additional GAS fee for the approvals of the named container
    registrations;
  * pass the config value to `WithCustomFeeForNamedPut` option of
    container morph client.

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>

pkg/morph/client/fee_test.go

@@ -0,0 +1,32 @@
+package client
+
+import (
+	"testing"
+
+	"github.com/nspcc-dev/neo-go/pkg/encoding/fixedn"
+	"github.com/stretchr/testify/require"
+)
+
+func TestFees(t *testing.T) {
+	var v fees
+
+	const method = "some method"
+
+	var (
+		fee fixedn.Fixed8
+		def = fixedn.Fixed8(13)
+	)
+
+	v.setDefault(def)
+
+	fee = v.feeForMethod(method)
+	require.True(t, fee.Equal(def))
+
+	const customFee = fixedn.Fixed8(10)
+
+	v.setFeeForMethod(method, customFee)
+
+	fee = v.feeForMethod(method)
+
+	require.Equal(t, customFee, fee)
+}