Import CMS code using fully qualified module names

or, using proper the proper Python 3 relative imports
(e.g., 'from .views import x') which are standard and
unambiguous.

cms/templates/settings.html

@@ -7,7 +7,7 @@
 <%namespace name='static' file='static_content.html'/>
 <%!
   from django.utils.translation import ugettext as _
-  from contentstore import utils
+  from cms.djangoapps.contentstore import utils
   from openedx.core.djangoapps.certificates.api import can_show_certificate_available_date_field
   from openedx.core.djangolib.js_utils import (
       dump_js_escaped_json, js_escaped_string