Move DnsProxyListener to libnetd_resolv
[1] Support APIs for netd to set callbacks and bring up
DnsProxyListener.
[2] Keep DnsProxyListener functioning as usual by function pointers,
including getNetworkContext(), checkCallingPermission(), and
getPrefix64().
[3] Use libbinder_ndk to report onDnsEvent().
Test: as follows
- built, flashed, booted
- system/netd/tests/runtests.sh passed
- netd_benchmark passed
- Browsing websites passed
Change-Id: Ib6575833c248579aa079e302795b6d6cddde1f2b
14 files changed