Remove dependency on libnetd_client

NetworkUtils can just use the NDK to achieve the same.

Also make sure network handles can have the local nameservers flag, for
the JNI API, and create/parse them accordingly in Network.

Bug: 171540887
Test: atest CtsNetTestCases (in particular MultinetworkApiTest,
          DnsResolverTest, NetworkTest)
Change-Id: I2e7b78263f7ca0cab9458854858a7423f6bd2854