Create debug endpoint for mobile user to trace ad rendering

[aram356]

Description

Create debug endpoint for mobile user to trace ad rendering

[aram356]

@jevansnyc Please let us know if you want engineers to start the spec

[aram356]

@prk-Jr to write spec

[aram356]

@prk-Jr Some notes from @jevansnyc

1. Network information (as example see https://www.fastly-debug.com)
2. Auction information per ad slot (similar to ts-tracer and metrics in telemetry PR)
3. End-user cookie information