INCR-248: Make compatible with Python 3.x without breaking Python 2.7… (#20529)

* INCR-248: Make compatible with Python 3.x without breaking Python 2.7 support --> common/djangoapps/xblock_django

* INCR-248: Grouped absolute_import and unicode_literals imports

* INCR-248: Grouped absolute_import and unicode_literals imports for migrations

common/djangoapps/xblock_django/admin.py

@@ -2,6 +2,8 @@
 Django admin dashboard configuration.
 """
 
+from __future__ import absolute_import
+
 from config_models.admin import ConfigurationModelAdmin, KeyedConfigurationModelAdmin
 from django.contrib import admin
 from django.utils.translation import ugettext_lazy as _

common/djangoapps/xblock_django/api.py

@@ -2,6 +2,8 @@
 API methods related to xblock state.
 """
 
+from __future__ import absolute_import
+
 from xblock_django.models import XBlockConfiguration, XBlockStudioConfiguration
 
 

common/djangoapps/xblock_django/models.py

@@ -2,6 +2,8 @@
 Models.
 """
 
+from __future__ import absolute_import
+
 from config_models.models import ConfigurationModel
 from django.db import models
 from django.utils.translation import ugettext_lazy as _

common/djangoapps/xblock_django/user_service.py

@@ -1,6 +1,8 @@
 """
 Support for converting a django user to an XBlock user
 """
+from __future__ import absolute_import
+
 from django.contrib.auth.models import User
 from opaque_keys.edx.keys import CourseKey
 from xblock.reference.user_service import UserService, XBlockUser