Support Tracking Domain

[YuriyVelichkoPI]

Background

According to the changes in Apple's privacy approach, some SDKs should register the Tracking Domain in the privacy manifest file.

For now, the Prebid SDK is not on the list of such SDKs. And it doesn't use a centralized server endpoint that can be caught by the Points of Interest instrument.

However, that time may come, or publishers may want to register the PBS endpoint in the privacy manifest proactively. For this case, the SDK should support both tracking and nontracking domains.

Objectives

• Introduce function Prebid.setCustomPrebidServer(url: String, trackingURL: String)
• If publishers provided trackingURL use it in when a user allowed the app to track. Otherwise - use the URL for the bid requests.