add audit log button

app/views/icons/_external_link.html.erb

@@ -0,0 +1,6 @@
+<svg xmlns="http://www.w3.org/2000/svg" class="<%= local_assigns[:class] %>" width="44" height="44" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round">
+  <path stroke="none" d="M0 0h24v24H0z" fill="none"></path>
+  <path d="M12 6h-6a2 2 0 0 0 -2 2v10a2 2 0 0 0 2 2h10a2 2 0 0 0 2 -2v-6"></path>
+  <path d="M11 13l9 -9"></path>
+  <path d="M15 4h5v5"></path>
+</svg>

app/views/submissions/show.html.erb

@@ -5,6 +5,12 @@
       <span class="text-3xl font-semibold focus:text-clip"><%= @submission.template.name %></span>
     </a>
     <div class="space-x-3 flex items-center">
+      <% if @submission.audit_trail.present? %>
+        <a href="<%= rails_blob_path(@submission.audit_trail) %>" class="white-button" target="_blank">
+          <%= svg_icon('external_link', class: 'w-6 h-6') %>
+          Audit Log
+        </a>
+      <% end %>
       <% if last_submitter = @submission.submitters.to_a.select(&:completed_at?).max_by(&:completed_at) %>
         <download-button data-src="<%= submitter_download_index_path(last_submitter.slug) %>" class="base-button">
           <span class="flex items-center justify-center space-x-2" data-target="download-button.defaultButton">