Clean up AddressSearch refactor - add support for defaultValue and use hint

[luacmartins]

Problem

Our AddressSearch component was refactored to work with Form, but we missed a couple of things during the refactor:

1. It should be able to load with a defaultValue
2. It should use a hint to display hint text. The hint should be replaced with an error message if there's one.

Why is this important

It standardizes the use of AddressSearch and follows the guidelines defined in the Forms design doc.

Solution

Add support for defaultValue and refactor usages of used as a hint for AddressSearch to the hint prop whenever possible.