A page to send students to which gives them a link to download a copy of all attempt data in local storage

[christianp]

When we're unsure if the student has attempt data in local storage that hasn't been uploaded to the server, it would be nice to have a page we can send them to that shows them all the Numbas attempt data saved in local storage, and gives them a link to download it.

[christianp]

The logic of this is wrong: if the student can access the LTI server, then we should just upload any data in local storage when they access a page.