Provide diagram as a partial

docs/latest/deployment/_nginx-image-archive-diagram.md

@@ -0,0 +1,4 @@
+<div style="text-align: center;">
+  <img src="/assets/img/nginx-image-archive.png" alt="request flow example" style="margin: 0 auto;" />
+  <div><i>simplified request flow diagram</i></div>
+</div>