Google Tag Manager consent mode

[felixgirault]

Provide a preset to setup a GTM integration.

This could mean a custom factory that :

• provides matching purposes with adequate translations

  {
    purposes: [
      {
        id: 'ad_storage',
        title: 'Ads'
      },
      {
        id: 'analytics_storage',
        title: 'Analytics'
      },
      // …
    ]
  }

• initializes consents

  gtag('consent', 'default', {
    'ad_storage': 'denied',
    'ad_user_data': 'denied',
    'ad_personalization': 'denied',
    'analytics_storage': 'denied'
  });

• updates consents

  window.orejime.manager.on('update', (diff) => {
    gtag(
      'consent', 
      'update', 
      mapValues((diff) => consent ? 'granted' : 'denied')
    );
  });

See https://developers.google.com/tag-platform/security/guides/consent?hl=fr&consentmode=advanced#tag-manager_1

[felixgirault]

See #120