Delete or hide auto-save entry when a document is saved to a device

[jaltekruse]

The auto-save list can currently become cluttered very easily. The serverless architecture of the app makes me less confident about instantly deleting the auto-saved entries, as users could lose track of their files. New users especially could fail to realize that the files end up in their download folders and feel that they have been lost.

This could instead by handled by adding a state to the auto-save of "recently saved", with some information about when it was saved to disk. These entires could possibly be hidden by default to keep the list cleaner. Indirection can cause confusion, they could also possibly appear grayed out instead.

[jaltekruse]

I am not very confident about removing the auto-saves in HTML5 local storage if users are saving to their downloads folders. I am completely avoiding these local auto-saves in the new branch that can save files directly to drive, including auto-saves while editing.