Add bpf support for NetworkStatsFactory

Add the native method used to read the detail information of network
stats from bpf maps. The native method of NetworkStatsFactory should
choose the correct implementation to get the stats detail depending on
the kernel version. Currently the bpf result is printed as a reference
and the actual behavior of NetworkStatsFactory should not change.

Test: NetworkStatsFactory related cts test should not fail.
Bug: 30950746
Change-Id: I4715a23559b5b2306bd556cea0431f0ed172a993