Add basic deadline to sections index

app/views/sections/index.html.erb

@@ -1,3 +1,21 @@
+<div class="deadline-info-container">
+    <div>
+        Je hebt nog
+        <span class="deadline-display" data-behaviour="deadline_display" data-deadline="<%= @deadline.httpdate %>">tijd tot <%= @deadline.to_fs(:short) %>.</span>
+    </div>
+    Je kan extra tijd krijgen door volgende dingen te organiseren. Je krijgt dan 6 weken extra.
+    <div class="extension-grid">
+        <% @extensions.each do |extension| %>
+            <div class="extension">
+                <span><%= extension.reason %></span>
+                <%= form_with url: confirm_extension_path(extension), method: :put do |form| %>
+                    <%= form.submit "Bevestig", disabled: extension.confirmed %>
+                <% end %>
+            </div>
+        <% end %>
+    </div>
+</div>
+
 <div class="title-card-grid">
     <% @sections.each do |section| %>
         <%= link_to(section_url(section), html_options = { class: 'title-card-container' }) do %>