made link preview optional

data/config.yaml

@@ -1,5 +1,6 @@
 name: Jacky Zhao
 enableToc: true
+enableLinkPreview: true
 description:
   Here is the page description. This is an example Quartz site that details installation,
   setup, customization, and troubleshooting for Quartz itself.

layouts/partials/popover.html

@@ -1,3 +1,4 @@
+{{if $.Site.Data.config.enableLinkPreview}}
 <script>
   function htmlToElement(html) {
     const template = document.createElement('template')
@@ -27,3 +28,4 @@
       })
   })
 </script>
+{{end}}