Fix up new Django 3.0 deprecations

Mostly text based: force/smart_text, ugettext_*

awx/main/models/inventory.py

@@ -14,7 +14,7 @@ import yaml
 # Django
 from django.conf import settings
 from django.db import models, connection
-from django.utils.translation import ugettext_lazy as _
+from django.utils.translation import gettext_lazy as _
 from django.db import transaction
 from django.core.exceptions import ValidationError
 from django.utils.timezone import now