Keep track of when public modules are copied.

[FrenjaminBanklin]

Currently there's no real way of knowing when somebody makes a copy of a module in the community collection. This may be useful to keep track of, and potentially down the road add a feature to potentially make it possible to overwrite a copy if updates are made to the community collection version of a module.

Possible extra/alternate ending - make it so that copies of community collection modules are read-only. This would enable instructors to embed a copy of a community module that they haven't changed but will allow them to check assessment stats.

It turns out metadata has been generated any time a module is copied that enables tracking down copies of modules, though this data isn't exposed anywhere outside of the database. I don't think it's super important to do so, but the ability to make read-only copies of modules that can be synced with the original at will might still be useful.