Permissions - Hide stocks from anonymous

[asbjornstokka]

It would be nice to be able to hide stocks from anonymous user, while allowing them to browse attachments and information about parts.

Describe the solution you'd like
A permission where it would be possible to limit user(s) from displaying the "stocks" tab, or not displaying the "amount" column in the stocks tab would be great.

Describe alternatives you've considered
I've considered not allowing anonymous users, or student users access the part database, and supplying them with the part information through the LMS. That would decrease the value of using partdb. And I've considered not keeping track of storage, also decreasing the value of using partdb.