[BOT.5] Move class Ipv6ForwardingRule from IpServer to the coordinator am: 39869f00bf am: 9636ff9812

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/11818380

Change-Id: I807acd45ab43fc91ba3e72f3c872580c4ee44c6c