#29: Custom camera overlay containing location accuracy

[aoblea]

Overview of changes

• Created a CustomCameraOverlayView
• Then added it to AddTreeViewController.swift
• Set image picker camera controls to false
• Assigned image picker overlay to custom camera overlay
• Added camera overlay view properties to addtreeviewmodel delegates for changes in location
• Added a white background to the overlay

How was the change tested

• Tested on actual device

Screenshots (if applicable)

[AlexCornforth]

Going to close this in favour of: https://github.com/Greenstand/treetracker-ios/pull/105