Move the 464xlat control plane from clatd to netd.

Some of this code comes from clatd and will be deleted from there
once this topic is merged.

Bug: 65674744
Test: builds, boots
Test: system/netd/tests/runtests.sh
Change-Id: Ifa30652a853401a401d0b74d259d4d27d322e758
9 files changed