feat: create feature flag for PLS custom pacing

cms/djangoapps/contentstore/config/waffle.py

@@ -67,3 +67,33 @@ REDIRECT_TO_LIBRARY_AUTHORING_MICROFRONTEND = LegacyWaffleFlag(
     flag_name='library_authoring_mfe',
     module_name=__name__,
 )
+
+
+# .. toggle_name: studio.pages_and_resources_mfe
+# .. toggle_implementation: CourseWaffleFlag
+# .. toggle_default: False
+# .. toggle_description: Waffle flag to link existing studio views to the new Pages and Resources experience.
+# .. toggle_use_cases: temporary, open_edx
+# .. toggle_creation_date: 2021-05-24
+# .. toggle_target_removal_date: 2021-12-31
+# .. toggle_warnings: Also set settings.COURSE_AUTHORING_MICROFRONTEND_URL.
+# .. toggle_tickets: None
+ENABLE_PAGES_AND_RESOURCES_MICROFRONTEND = CourseWaffleFlag(
+    waffle_namespace=waffle_flags(),
+    flag_name='pages_and_resources_mfe',
+    module_name=__name__,
+)
+
+# .. toggle_name: studio.custom_pls
+# .. toggle_implementation: CourseWaffleFlag
+# .. toggle_default: False (except for SuperUsers)
+# .. toggle_description: Waffle flag to enable custom pacing for PLS
+# .. toggle_use_cases: temporary
+# .. toggle_creation_date: 2021-06-15
+# .. toggle_target_removal_date: 2021-12-31
+# .. toggle_warnings: None
+# .. toggle_tickets: None
+CUSTOM_PLS = CourseWaffleFlag(WAFFLE_NAMESPACE, 'custom_pls', module_name=__name__,)
+
+def custom_pls_is_active(course_key):
+    return CUSTOM_PLS.is_enabled(course_key)

cms/djangoapps/contentstore/views/item.py

@@ -2,7 +2,7 @@
 
 import logging
 from collections import OrderedDict
-from datetime import datetime
+from datetime import datetime, timedelta
 from functools import partial
 from uuid import uuid4