Added middleware to bypass authorization in load testing

The MainTheme set the splash screen image as the window background.
I’ve removed this and ensured that the SplashActivity is the launch
activity.

Also did some code tidy up on the Campaign page classes.

Added Payment.api to healthcheck

Fixed Checkout process
Changed some UWP icons

This ensures the launch storyboard doesn’t generate an error, and is
line with Xamarin policy for samples.

or namespace name 'Models' does not exist in the namespace 'Identity.API' (are you missing an assembly reference?)

Created input in user campaigns view to update the user's location