add picture lightbox

Signed-off-by: Michel-FK <michel.stempin@funkey-project.com>

docs/assets/js/custom.js

@@ -0,0 +1,24 @@
+$(document).ready(function () {
+  let imageGroups = []
+  $(".lightbox").each(function () {
+    let imageSource = $(this).attr('src')
+    let imageTag = $(this).attr('tag')
+    let imageTitle = $(this).attr('title')
+    if (imageTitle) {
+      imageTitle = 'title="' + imageTitle + '" '
+    }
+    else {
+      imageTitle = ''
+    }
+    $(this).
+        wrap('<a class="boxedThumb ' + imageTag + '" ' +
+            imageTitle + 'href="' + imageSource + '"></a>')
+    imageGroups.push('.' + imageTag)
+  })
+  jQuery.unique(imageGroups)
+  imageGroups.forEach(imageGroupsSet)
+
+  function imageGroupsSet (value) {
+    $(value).simpleLightbox()
+  }
+})