Add email notification for staff

templates/emails/staff_verify.body.txt

@@ -0,0 +1,23 @@
+Hi,
+
+A new print has been submitted and has just passed the automated checks.
+It is now waiting for a staff verification before it can enter the print
+queue.
+
+    Codename : {{ submission.slug }}
+    Source   : {{ submission.source_label }}
+    Submitter: {% if submission.submitted_by_id %}{{ submission.submitted_by.email }} (signed in){% else %}{{ submission.guest_email }} (guest, email confirmed){% endif %}
+    Filament : {% if submission.requested_filament %}{{ submission.requested_filament.display_label }}{% else %}No preference{% endif %}
+{% if submission.notes_for_op %}
+Notes the submitter left for you:
+
+    {{ submission.notes_for_op }}
+{% endif %}
+Review the submission in admin:
+    {{ admin_url }}
+
+Public detail page:
+    {{ detail_url }}
+
+— hamprint
+{{ site_url }}