Adds retry page

bookwyrm/templates/import/import_status.html

@@ -32,12 +32,28 @@
         </div>
     </div>
     {% endif %}
+
+    {% if complete and fail_count %}
+    <div class="notification is-warning">
+        {% blocktrans trimmed count counter=fail_count with display_counter=fail_count|intcomma %}
+            {{ display_counter }} item failed to import.
+            {% plural %}
+            {{ display_counter }} items failed to import.
+        {% endblocktrans %}
+        <a href="{% url 'import-troubleshoot' job.id %}">
+            {% trans "View and troubleshoot failed items." %}
+        </a>
+    </div>
+    {% endif %}
 </header>
 
 <div class="block">
     <h2 class="title is-4">
+        {% block page_title %}
         {% trans "Your Import" %}
+        {% endblock %}
     </h2>
+    {% block actions %}{% endblock %}
     <table class="table">
         <tr>
             <th>

bookwyrm/templates/import/troubleshoot.html

@@ -0,0 +1,30 @@
+{% extends 'import/import_status.html' %}
+{% load i18n %}
+
+{% block title %}{% trans "Import Troubleshooting" %}{% endblock %}
+
+{% block page_title %}
+{% trans "Failed items" %}
+{% endblock %}
+
+{% block actions %}
+<div class="block">
+    <div class="notification content">
+        <p>
+            {% trans "Re-trying an import can fix missing items in cases such as:" %}
+            <ul>
+                <li>{% trans "The book has been added to the instance since this import" %}</li>
+                <li>{% trans "A transient error or timeout caused the external data source to be unavailable." %}</li>
+                <li>{% trans "BookWyrm has been updated since this import with a bug fix" %}</li>
+            </ul>
+        </p>
+        <p>
+        {% trans "Contact your admin or <a href='https://github.com/bookwyrm-social/bookwyrm/issues'>open an issue</a> if you are seeing unexpected failed items." %}
+        </p>
+    </div>
+    <form name="retry" method="post" action="{% url 'import-troubleshoot' job.id %}">
+        {% csrf_token %}
+        <button type="submit" class="button">Retry all</button>
+    </form>
+</div>
+{% endblock %}