Fixes a couple of bugs that prevented proper menu rendering on mobile.
Updates urls so that the deprecated 'section' view used by two_lvl
menus does not hide the newer and improved menu view. Centralizes
conversion of str into ObjectId into get_mongo_id in dal/mongo.py to
avoid code duplication, simplify the logic in some functions, and
output more consistent logging. Fixes a bug in init_session where
menu() was called with a menu object rather than a menu id.