GA: Add Google Analytics snippets

Signed-off-by: Youngsoo Shin <sysx114@gmail.com>

Writerside/cfg/buildprofiles.xml

@@ -6,6 +6,8 @@
     <variables>
         <search-endpoint>https://search.sys114.com</search-endpoint>
         <web-root>https://docs.sys114.com</web-root>
+        <analytics-head-script-file>google.head.html</analytics-head-script-file>
+        <analytics-body-html-file>google.body.html</analytics-body-html-file>
     </variables>
     <build-profile instance="d">
         <variables>

Writerside/cfg/google.head.html

@@ -0,0 +1,9 @@
+<!-- Google tag (gtag.js) -->
+<script async src="https://www.googletagmanager.com/gtag/js?id=G-8BTPRBKJ5B"></script>
+<script>
+    window.dataLayer = window.dataLayer || [];
+    function gtag(){dataLayer.push(arguments);}
+    gtag('js', new Date());
+
+    gtag('config', 'G-8BTPRBKJ5B');
+</script>->