Rename form objects to remove the term ‘whitelist’

See c31264d4c for rationale. To avoid confusion the codebase should use
the same terminology as the UI.

app/main/forms.py

@@ -1241,26 +1241,26 @@ class PDFUploadForm(StripWhitespaceForm):
     )
 
 
-class EmailFieldInWhitelist(EmailField, StripWhitespaceStringField):
+class EmailFieldInGuestList(EmailField, StripWhitespaceStringField):
     pass
 
 
-class InternationalPhoneNumberInWhitelist(InternationalPhoneNumber, StripWhitespaceStringField):
+class InternationalPhoneNumberInGuestList(InternationalPhoneNumber, StripWhitespaceStringField):
     pass
 
 
-class Whitelist(StripWhitespaceForm):
+class GuestList(StripWhitespaceForm):
 
     def populate(self, email_addresses, phone_numbers):
-        for form_field, existing_whitelist in (
+        for form_field, existing_guest_list in (
             (self.email_addresses, email_addresses),
             (self.phone_numbers, phone_numbers)
         ):
-            for index, value in enumerate(existing_whitelist):
+            for index, value in enumerate(existing_guest_list):
                 form_field[index].data = value
 
     email_addresses = FieldList(
-        EmailFieldInWhitelist(
+        EmailFieldInGuestList(
             '',
             validators=[
                 Optional(),
@@ -1274,7 +1274,7 @@ class Whitelist(StripWhitespaceForm):
     )
 
     phone_numbers = FieldList(
-        InternationalPhoneNumberInWhitelist(
+        InternationalPhoneNumberInGuestList(
             '',
             validators=[
                 Optional()