Generalize analytics support in default theme

As the number of privacy-preserving analytics options proliferates,
it no longer makes sense to support specific solutions provided by
ad-tracking corporations.

docs/publish.rst

@@ -67,7 +67,7 @@ Deployment
 
 After you have generated your site, previewed it in your local development
 environment, and are ready to deploy it to production, you might first
-re-generate your site with any production-specific settings (e.g., analytics
+re-generate your site with any production-specific settings (e.g., analytics,
 feeds, etc.) that you may have defined::
 
     pelican content -s publishconf.py

docs/settings.rst

@@ -1245,18 +1245,19 @@ Feel free to use them in your themes as well.
    Your GitHub URL (if you have one). It will then use this information to
    create a GitHub ribbon.
 
-.. data:: GOOGLE_ANALYTICS
+.. data:: ANALYTICS
 
-   Set to ``UA-XXXXX-Y`` Property's tracking ID to activate Google Analytics.
+   Put any desired analytics scripts in this setting in ``publishconf.py``.
+   Example:
 
-.. data:: GA_COOKIE_DOMAIN
-
-   Set cookie domain field of Google Analytics tracking code. Defaults to
-   ``auto``.
-
-.. data:: GOSQUARED_SITENAME
+   .. parsed-literal::
 
-   Set to 'XXX-YYYYYY-X' to activate GoSquared.
+      ANALYTICS = """
+          <script src="/theme/js/primary-analytics.js"></script>
+          <script>
+              [ … in-line Javascript code for secondary analytics … ]
+          </script>
+      """
 
 .. data:: MENUITEMS
 

pelican/themes/notmyidea/templates/analytics.html

@@ -1,26 +1,3 @@
-{% if GOOGLE_ANALYTICS %}
-    <script type="text/javascript">
-    (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
-    (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
-    m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
-    })(window,document,'script','https://www.google-analytics.com/analytics.js','ga');
-
-    ga('create', '{{GOOGLE_ANALYTICS}}', '{{GA_COOKIE_DOMAIN if GA_COOKIE_DOMAIN else 'auto'}}');
-    ga('send', 'pageview');
-    </script>
-{% endif %}
-{% if GAUGES %}
-    <script type="text/javascript">
-    var _gauges = _gauges || [];
-    (function() {
-        var t   = document.createElement('script');
-        t.type  = 'text/javascript';
-        t.async = true;
-        t.id    = 'gauges-tracker';
-        t.setAttribute('data-site-id', '{{GAUGES}}');
-        t.src = '//secure.gaug.es/track.js';
-        var s = document.getElementsByTagName('script')[0];
-        s.parentNode.insertBefore(t, s);
-    })();
-    </script>
+{% if ANALYTICS %}
+{{ ANALYTICS }}
 {% endif %}