Add bpf map and lock for UidOwnerMap

This commit is a preparation for replacing JNI codes that modify
UidOwnerMap by Java.

Bug: 217624062
Test: atest BpfNetMapsTest HostsideRestrictBackgroundNetworkTests
android.net.cts.ConnectivityManagerTest#testFirewallBlocking

Change-Id: Ie595cf1f77a3ed86addbcdaea1a1be972e0265b3
3 files changed