Add table of contents to book pages

We have titles, might as well

Author: KnightMiner

_includes/book/pages.html

@@ -3,6 +3,20 @@
   Click a page to view in gallery mode.
 </p>
 
+{% if include.book.titles %}
+<div class="uk-card uk-card-default uk-card-body uk-card-small toc">
+  <ul uk-accordion><li class="uk-open">
+    <a class="uk-accordion-title" href>Table of Contents</a>
+    <div class="uk-accordion-content section-list"><ol>
+      {% for title in include.book.titles %}
+        <li><a href="#{{ title.text | slugify }}">{{title.text}}</a></li>
+      {% endfor %}
+    </ol></div>
+  </li></ul>
+</div>
+<br/>
+{% endif %}
+
 <div uk-lightbox="animation: slide; toggle: .book-page">
     <div class="uk-child-width-1-1 uk-child-width-1-3@s uk-grid-collapse" uk-grid>
         {%- unless include.book.no_cover -%}