[#257] Support flag to deny access if policy rules not found

Signed-off-by: Denis Kirillov <d.kirillov@yadro.com>

api/router_mock_test.go

@@ -20,7 +20,9 @@ func (c *centerMock) Authenticate(*http.Request) (*middleware.Box, error) {
 	return &middleware.Box{}, nil
 }
 
-type middlewareSettingsMock struct{}
+type middlewareSettingsMock struct {
+	denyByDefault bool
+}
 
 func (r *middlewareSettingsMock) NamespaceHeader() string {
 	return FrostfsNamespaceHeader
@@ -30,6 +32,10 @@ func (r *middlewareSettingsMock) ResolveNamespaceAlias(ns string) string {
 	return ns
 }
 
+func (r *middlewareSettingsMock) PolicyDenyByDefault() bool {
+	return r.denyByDefault
+}
+
 type handlerMock struct {
 	t *testing.T
 }