Move the below build targets to api/video:

- adapted_video_track_source
- video_adapter
- video_broadcaster
- video_common

These targets are meant to replace rtc_media_base.

Change-Id: Iaa69cd8379f66f98d618ac2e4fb6ffb4a1806f50
Bug: webrtc:42225070
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/483960
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Reviewed-by: Erik Språng <sprang@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Jeremy Leconte <jleconte@google.com>
Cr-Commit-Position: refs/heads/main@{#48064}