Add server side invalid document template

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

mayan/apps/documents/templates/documents/invalid_document.html

@@ -0,0 +1,11 @@
+{% spaceless %}
+<div class="text-center" style="border: height: 100%;">
+    <div class="fa-4x">
+        <span class="fa-layers fa-fw">
+            <i class="far fa-file text-primary"></i>
+            <i class="fas fa-times text-danger" data-fa-transform="shrink-8"></i>
+        </span>
+    </div>
+</div>
+{% endspaceless %}
+