Add salutation "Mx", normalize salutations (save in English, localize on display) (#2075)

* normalize salutations and localize before use

* add migration to normalize salutations

* add placeholder "name_for_salutation" for emails

src/pretix/base/migrations/0187_normalize_salutation.py

@@ -0,0 +1,62 @@
+# Generated by Django 3.2.2 on 2021-05-11 06:55
+
+from django.conf import settings
+from django.db import migrations
+from django.utils.translation import pgettext
+
+from pretix.base.i18n import language
+from pretix.base.settings import PERSON_NAME_SALUTATIONS
+
+
+def normalize_salutations(apps, schema_editor):
+    models = (
+        ("pretixbase", "Customer", "name_parts"),
+        ("pretixbase", "InvoiceAddress", "name_parts"),
+        ("pretixbase", "Membership", "attendee_name_parts"),
+        ("pretixbase", "CartPosition", "attendee_name_parts"),
+        ("pretixbase", "OrderPosition", "attendee_name_parts"),
+        ("pretix_exhibitors", "Exhibitor", "contact_name_parts"),
+    )
+
+    for salutation, value in PERSON_NAME_SALUTATIONS:
+        salutations = []
+        for lang in settings.LANGUAGES:
+            with language(lang[0]):
+                salutation_localized = pgettext("person_name_salutation", salutation)
+                if (
+                    salutation_localized != salutation
+                    and salutation_localized not in salutations
+                ):
+                    salutations.append(salutation_localized)
+
+        for app, model, key in models:
+            sort_params = {}
+            sort_params["{}__salutation__in".format(key)] = salutations
+            try:
+                m = apps.get_model(app, model)
+            except LookupError:
+                continue
+            try:
+                qs = m.objects
+            except AttributeError:
+                qs = m.all
+
+            for o in qs.filter(**sort_params):
+                val = getattr(o, key)
+                val["salutation"] = salutation
+                setattr(o, key, val)
+                o.save()
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("pretixbase", "0186_invoice_sent_to_organizer"),
+    ]
+
+    operations = [
+        migrations.RunPython(
+            normalize_salutations,
+            migrations.RunPython.noop,
+        ),
+    ]