Allow to save default value for branch selection when reserving items

[johan12345]

When reserving an item and the library asks you to select which branch it should be delivered to, it should be possible to save the selection as a default value. The app then needs to remember this selection and give it back to the API the next time.

We need to think about a good GUI to then remove this default later.

Proposed by internal support ticket # 2335514