Improve user interface showing a change log entry

Don't use <label> tags for things that are not labels, add a proper
<title> for the page, add a back link, remove an unnecessary
`inline-block` style for a header, localize dates and field names, ...

The interface could be further improve: proper diffs for long texts,
better separation between fields, ...

app/helpers/audits_helper.rb

@@ -1,11 +1,15 @@
 module AuditsHelper
   def truncate_audit_value(resource, field, value)
+    truncate(audit_value(resource, field, value), length: 50)
+  end
+
+  def audit_value(resource, field, value)
     if value.is_a?(Array)
-      truncate(value.join(","), length: 50)
+      value.join(",")
     elsif resource.type_for_attribute(field.to_s).type == :boolean
       resource.class.human_attribute_name("#{field}_#{value}")
     else
-      truncate(value.to_s, length: 50)
+      value.to_s
     end
   end
 end