Deprecate escaping in display_name_with_default

- Remove escaping in display_name_with_default
- Move escaped version to deprecated display_name_with_default_escaped
- Does not include any other changes to remove double-escaping

Thanks to agaylard who initiated this work:
https://github.com/edx/edx-platform/pull/10756

TNL-3425

cms/templates/base.html

@@ -16,9 +16,9 @@ from openedx.core.lib.js_utils import (
         <%block name="title"></%block> |
         % if context_course:
         <% ctx_loc = context_course.location %>
-        ${context_course.display_name_with_default | h} |
+        ${context_course.display_name_with_default_escaped | h} |
         % elif context_library:
-        ${context_library.display_name_with_default | h} |
+        ${context_library.display_name_with_default_escaped | h} |
         % endif
         ${settings.STUDIO_NAME}
     </title>
@@ -81,7 +81,7 @@ from openedx.core.lib.js_utils import (
               require(['js/factories/course'], function(CourseFactory) {
                   CourseFactory({
                       id: "${escape_js_string(context_course.id) | n}",
-                      name: "${context_course.display_name_with_default | h}",
+                      name: "${context_course.display_name_with_default_escaped | h}",
                       url_name: "${context_course.location.name | h}",
                       org: "${context_course.location.org | h}",
                       num: "${context_course.location.course | h}",