Saved extras and pickup locations

Both live on /owners/settings.

• Saved extras. Something a renter can add at checkout, with a name, a price, and per trip or per day billing. Start from the catalog or write your own. On any car's edit page, Add from your saved extras puts one on that car.
• Saved pickup locations. A street address, a pickup fee and instructions for the renter. In the listing wizard and on the edit page, the saved locations dropdown adds one to the car.

Attaching a saved item makes a copy on that car. Editing the saved version later doesn't change cars you've already set up.