User favorites API #56
Description
We need an API to fulfill the following user stories:
- As a user, I want to track multiple locations where I want to keep track of air quality so that I am on top of things without repeating the same search each time.
- As a user I should be able to save a sensor to my favorites so that it will appear on a favorite view with labels so that I can see them easily
- As a user I should be able to rename a favorite sensor
- As a user I should be able to stop tracking a sensor as a favorite location.