Support RDNS on cache and uid/pid tagging

RDNS on local cache

Function that performs RDNS on local cache. Takes
ip address and net id as input and gives domain
name as output.

Tag DNS query

Function that tags the uid and pid of the application
that sends DNS query.

Bug: 131051938
Test: build, flash, boot

Change-Id: I34abfc63d65f37e00dd813c9121ff483e4f85e7d