layouts: Test for existence of Google Analytics ID

Previously we showed the Cookie Usage banner if the site's config
had a cookie consent URL specified. As of 2018-05 (GDPR) it makes
more sense to only display this banner if the site has a Google
Analytics ID set. Because we are using Haven for consent manage-
ment we can now inject Google Analytics automatically after the
user has agreed, so we no longer need to use Hugo's internal te-
mplate.

layouts/_default/baseof.html

@@ -31,9 +31,7 @@
       {{ printf `<link rel="%s" type="%s" href="%s" title="%s" />` .Rel .MediaType.Type .Permalink $.Site.Title | safeHTML }}
     {{ end -}}
 
-    {{ template "_internal/google_analytics_async.html" . }}
-
-    {{ if .Site.Params.cookie_consent_info_url }}
+    {{ if .Site.GoogleAnalytics }}
     {{ partial "cookie-consent.html" . }}
     {{ end }}
 

layouts/partials/cookie-consent.html

@@ -26,7 +26,7 @@ Haven.create({
         {
             name: 'google-analytics',
             options: {
-                    id: '{{ .Site.Params.googleAnalytics }}',
+                    id: {{ .Site.GoogleAnalytics }},
             },
             purposes: ['analytics'],
             inject: true,