Rename DefaultNetworkSimulationConfig into BuiltInNetworkBehaviorConfig.
Rename DefaultNetworkSimulationConfig into BuiltInNetworkBehaviorConfig.

It is done to better show what for this class exists and also restore
correspondence between config and interface, that is implemented by
configurable object.

Bug: webrtc:9630
Change-Id: I28456d1c792d67d9b2a405c8599054137a5d596a
Reviewed-on: https://webrtc-review.googlesource.com/c/104003
Commit-Queue: Artem Titov <1e27363ccc366a7ff0fdde48204d68d5ebfeccc5@webrtc.org>
Reviewed-by: Sebastian Jansson <c24d1bc144eb7c11e553f59153fa17dba85ca83e@webrtc.org>
Reviewed-by: Karl Wiberg <2c708eb0a58047bf403399f50b3da33ffd2dd444@webrtc.org>
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#25041}
TimothyGu/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc