Add page taxonomy links for tags and categories

- Customizable text via _data file
- Enable/disable links by setting archive page filenames in _config.yml

_pages/collection-archive.html

@@ -12,7 +12,7 @@ author_profile: false
   {% unless collection.output == false or collection.label == 'posts' %}
     {% capture label %}{{ collection.label }}{% endcapture %}
     {% if label != written_label %}
-      <h2 class="archive__subtitle">{{ label }}</h2>
+      <h2 id="{{ label | slugify }}" class="archive__subtitle">{{ label }}</h2>
       {% capture written_label %}{{ label }}{% endcapture %}
     {% endif %}
   {% endunless %}