Docs: add google analytics, baidu and clarity (#1629)

Signed-off-by: Carson Yang <yangchuansheng33@gmail.com>

docSite/layouts/partials/docs/analytics/baidu.html

@@ -0,0 +1,18 @@
+<!-- baidutongji -->
+<script defer>
+  function loadScriptOnScroll() {
+    var scrollPosition = window.scrollY || window.pageYOffset;
+
+    if (scrollPosition > 100) {
+      var _hmt = _hmt || [];
+      var hm = document.createElement("script");
+      hm.src = "https://hm.baidu.com/hm.js?537c7867df8f9ae2e7147284ec0dbfdd";
+      var s = document.getElementsByTagName("script")[0]; 
+      s.parentNode.insertBefore(hm, s);
+
+      window.removeEventListener('scroll', loadScriptOnScroll);
+    }
+  }
+
+  window.addEventListener('scroll', loadScriptOnScroll);
+</script>