Add scarf tracking pixel to docs footer

Author: MarkWoulfeNeo4j

src/partials/footer-content.hbs

@@ -1,6 +1,6 @@
 <footer class="footer">
   <div class="wrapper">
-
+  <img referrerpolicy="no-referrer-when-downgrade" src="https://static.scarf.sh/a.png?x-pxid=dae9b690-6a56-4889-a951-9d0207a18da6" />
   <div class="column logo">
     <div class="logo-footer"></div>
   </div>