Add possibility to configure min bitrate based on resolution.
Only adapt up if bw estimate is above the min bitrate for next higher resolution.
Bug: none
Change-Id: Ie38faae07d23336675ec33697ace6f6fed322efa
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/148598
Reviewed-by: Magnus Flodman <mflodman@webrtc.org>
Commit-Queue: Åsa Persson <asapersson@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28863}