Fixed #19139 -- Made OpenLayersWidget follow GeoModelAdmin's modifiable attribute

Thanks Tim Graham for the review.
Prevented Attribute error in GDAL objects deletion
Fixed #13843 -- Prevented AttributeError during geometry objects deletion
Fixed #17101 -- Integrated django-secure and added check --deploy option

Thanks Carl Meyer for django-secure and for reviewing.

Thanks also to Zach Borboa, Erik Romijn, Collin Anderson, and
Jorge Carleitao for reviews.
Added ops team to roles.txt.
Fixed #23483 -- Prevented ImproperlyConfigured with dotted app names

Made sure the app labels stay unique for the AppConfigStubs, so
migrations wouldn't fail if two dotted app names has the same last part
(e.g. django.contrib.auth and vendor.auth)
Fixed #23484 -- Add comment in AppConfigStub clarifying app name vs app label.