Permalink & date fixes (#1)

* remove last_modified_at section on every pages

* remove "permalink" in front matter of base pages

    - it works by default

_layouts/single.html

@@ -55,8 +55,6 @@ layout: default
         {% include page__taxonomy.html %}
         {% if page.last_modified_at %}
           <p class="page__date"><strong><i class="fas fa-fw fa-calendar-alt" aria-hidden="true"></i> {{ site.data.ui-text[site.locale].date_label | default: "Updated:" }}</strong> <time datetime="{{ page.last_modified_at | date: "%Y-%m-%d" }}">{{ page.last_modified_at | date: "%B %d, %Y" }}</time></p>
-        {% elsif page.date %}
-          <p class="page__date"><strong><i class="fas fa-fw fa-calendar-alt" aria-hidden="true"></i> {{ site.data.ui-text[site.locale].date_label | default: "Updated:" }}</strong> <time datetime="{{ page.date | date_to_xmlschema }}">{{ page.date | date: "%B %d, %Y" }}</time></p>
         {% endif %}
       </footer>
 

_pages/activites.md

 ---
 title: Nos activités
 category_name: "activite"
-permalink: "/activites/"
 toc: true
 header:
   overlay_image: assets/images/banniere-parvis.jpg

_pages/ccl.md

 ---
 title: Le CCL
 category_name: "ccl"
-permalink: "/ccl/"
 header:
   image: assets/images/banniere-ccl-intime.png
   og_image: assets/images/logo-com-grand.png

_pages/luminy.md

 ---
 title: Luminy c'est aussi
 category_name: "luminy"
-permalink: "/luminy/"
 toc: true
 header:
   overlay_image: assets/images/banniere-hexagone.png