config: Add the foundation for GDPR privacy configuration

See #4616

config/privacy/privacyConfig.go

@@ -0,0 +1,85 @@
+// Copyright 2018 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package privacy
+
+import (
+	"github.com/gohugoio/hugo/config"
+	"github.com/mitchellh/mapstructure"
+)
+
+const privacyConfigKey = "privacy"
+
+// Service is the common values for a service in a policy definition.
+type Service struct {
+	Disable bool
+}
+
+// Config is a privacy configuration for all the relevant services in Hugo.
+type Config struct {
+	Disqus          Disqus
+	GoogleAnalytics GoogleAnalytics
+	Instagram       Instagram
+	SpeakerDeck     SpeakerDeck
+	Tweet           Tweet
+	Vimeo           Vimeo
+	YouTube         YouTube
+}
+
+// Disqus holds the privacy configuration settings related to the Disqus template.
+type Disqus struct {
+	Service `mapstructure:",squash"`
+}
+
+// GoogleAnalytics holds the privacy configuration settings related to the Google Analytics template.
+type GoogleAnalytics struct {
+	Service `mapstructure:",squash"`
+}
+
+// Instagram holds the privacy configuration settings related to the Instagram shortcode.
+type Instagram struct {
+	Service `mapstructure:",squash"`
+}
+
+// SpeakerDeck holds the privacy configuration settings related to the SpeakerDeck shortcode.
+type SpeakerDeck struct {
+	Service `mapstructure:",squash"`
+}
+
+// Tweet holds the privacy configuration settingsrelated to the Tweet shortcode.
+type Tweet struct {
+	Service `mapstructure:",squash"`
+}
+
+// Vimeo holds the privacy configuration settingsrelated to the Vimeo shortcode.
+type Vimeo struct {
+	Service `mapstructure:",squash"`
+}
+
+// YouTube holds the privacy configuration settingsrelated to the YouTube shortcode.
+type YouTube struct {
+	Service  `mapstructure:",squash"`
+	NoCookie bool
+}
+
+func DecodeConfig(cfg config.Provider) (pc Config, err error) {
+	if !cfg.IsSet(privacyConfigKey) {
+		return
+	}
+
+	m := cfg.GetStringMap(privacyConfigKey)
+
+	err = mapstructure.WeakDecode(m, &pc)
+
+	return
+}