This cl move VideoEncoderConfig from api/ to video/config. VideoStreamEncoderInterface and VideoStreamEncoderObserver are moved as collateral. brandt@ think that the reason these were in api/ in the first place had to downstream project. Functionality wise, this is a NOP, but it makes it easier to modify the encoder (config). Bug: webrtc:14451 Change-Id: I2610d815aeb186298498e7102cac773ecac8cd36 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/277002 Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org> Reviewed-by: Rasmus Brandt <brandtr@webrtc.org> Reviewed-by: Artem Titov <titovartem@webrtc.org> Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org> Commit-Queue: Jonas Oreland <jonaso@webrtc.org> Cr-Commit-Position: refs/heads/main@{#38242}