Move some constants from TrafficStatsConstants to NetworkStackConstants

Keep the constants are only used by framework in TrafficStatsConstants
and move the others to NetworkStackConstants which is in libs/net.

Bug: 182349970
Test: FrameworksNetTests
      NetworkStackTests
      TetheringTests
Change-Id: Ib667c115e5f1e01237d88b77bba753363da309cc