convert rtc_base/network and collateral. This also remove last usage of system_wrappers/field_trials in p2p/...Yay! Bug: webrtc:10335 Change-Id: Ie8507b1f52bf7f3067e9b4bf8c81a825e4644fda Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/256640 Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org> Reviewed-by: Harald Alvestrand <hta@webrtc.org> Commit-Queue: Jonas Oreland <jonaso@webrtc.org> Cr-Commit-Position: refs/heads/main@{#36357}