Return items on a reservation

[jim]

What it does

• Adds the ability for a staff member to mark items on a reservation as returned at the end of a loan.
• Restructures the "Pickups" tab to be the "Items" tab on a reservation. Now all item manipulation (both while building up the specific items to be borrowed and when they are returned later on) happen on the same page/tab.
• Deletes an unused partial: app/views/account/reservations/_profile.html.erb.

Why it is important

We need to have a accept items that are returned to us 😄

UI Change Screenshot

Implementation notes

• It's possible we could avoid the turbo stream shenanigans in this flow, but I started working on this before we merged in the page refresh morphing stuff in Add flash_highlight and clean up bits of old highlighting. #1738. I will see if that simplification is possible while tackling future parts of the reservation flow.

[crismali]

full turbo 🔥