Cookie Refactor

[cjreed121]

We currently have a variety of cookies throughout our system. Some of them are scoped correctly but some still store in the global scope. In course materials, we store a cm_folder_data cookie in the global scope which stores a lot of data. Cookies have a limit of 4096 bytes and there is also an overall size limit of an HTTP request for Apache.

There is a couple things which need to be done (can be split up into multiple issues):

• [ ] cm_folder_data should be switched from global scope to the URL of course materials. cm_folder_data also stores the entire system path of each course material which should be shortened to either ID or a relative path.
• [ ] anon_mode_{} exists for each gradeable and also exists in the global scope. This should be refactored to be in the specific gradeable scope.
• [ ] The same applies for default_anon_mode_{}_override.
• [ ] We should look if there are any other instances that need this change too.

[skara9]

We should also look into switching over to local storage instead of cookies, since it's much more efficient for storing client-side data that doesn't need to be sent to the server on every request.