Automation of moving lists to Stale

[collinbarrett]

Currently, lists are included in the Stale list type if they have not been updated in the past year. This is a manual process, and it will be hard to keep updated. We should eliminate the Stale list type .json file (moving all of its current lists to their most appropriate other list type) and instead display lists on the Stale page by an automated check of their last updated date.

Requires #6

[collinbarrett]

Won't fix. Instead the last-updated date, when it is able to be acquired, will be publicly available and factored into the FilScore. A separate "stale" page will no longer be maintained.