aardvark - schain and ccpa support

[aleksatr]

Type of change

• Feature

Description of change

• When building request, read bidderRequest.uspConsent and pass it as us_privacy query param.
• Add us_privacy query param when creating user sync frame.

There's also PR for 3.x version here: #4775
Docs update can be found here: prebid/prebid.github.io#1765

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• Add support for SupplyChain (schain) in aardvark bid adapter.
• Serialize schain object into string and pass it as a query parameter to aardvark bidder.

Schain related changes are already merged in 3.x, MR that introduced them in 3.x can be found here: #4636
Docs update for schain support has already been merged (prebid/prebid.github.io#1740)

• official adapter submission