Adding interaction controls for ads.

[benhumphry]

Proposed Changes for OpenRTB 2.6.x: supporting interaction type with controls

already widely adopted and in use by mobile advertising platforms:

Those parameters are used in all kinds of mobile ads, such as native, banner, video and so on.
Many advertisers, ad platforms and SSPs who focusing on mobile ads, such as Ocean Engine, Kuaishou Technology, Meitu, Tecent, Baidu and Xiaomi, are using those parameters in almost all of their bid requests and bid responses.
These proposed changes will align OpenRTB 2.6.x with this real world usage in China and beyond.