added title, subtitle, and description to example page

Author: kalwalt

examples/index.html

@@ -1,5 +1,8 @@
 ---
 layout: page
+title: WebAR Kit example page
+subtitle: Some examples with variuos AR projects
+description: We collect in this page some examples with our developed software for WebAR: ArtoolkitX.js, Jsartoolkit5, ARnft, JsartoolkitNFT and more
 ---
 <div>
   <a href="/examples/simple_2d_tracking.html"><h2>ArtoolkitX.js example with 2d tracking</h2></a>