Add generic send_email task in wagtailadmin.tasks

This will be used from the send form data to email. It has been added to
the wagtailadmin.tasks module to use celery if it has been defined and
configured or just send the email if not (just like the
send_notification task).

wagtail/wagtailadmin/tasks.py

@@ -85,3 +85,16 @@ def send_notification(page_revision_id, notification, excluded_user_id):
 
     # Send email
     send_mail(email_subject, email_content, from_email, email_addresses)
+
+
+@task
+def send_email_task(email_subject, email_content, from_email, email_addresses):
+    if not from_email:
+        if hasattr(settings, 'WAGTAILADMIN_NOTIFICATION_FROM_EMAIL'):
+            from_email = settings.WAGTAILADMIN_NOTIFICATION_FROM_EMAIL
+        elif hasattr(settings, 'DEFAULT_FROM_EMAIL'):
+            from_email = settings.DEFAULT_FROM_EMAIL
+        else:
+            from_email = 'webmaster@localhost'
+
+    send_mail(email_subject, email_content, from_email, email_addresses)