Update settings file templates to support 3.x imports

go/settings/settings.docker.py.template

 #Create a new file 'settings.py' and copy these contents into that file
-import secret
+from . import secret
 import os
 
 AUTH_MODE = "CAS"

go/settings/settings.py.template

 # Create a new file 'settings.py' and copy these contents into that file
-import secret
+from . import secret
 import os
 import sys