IpManager: define InitialConfiguration

This patch adds a InitialConfiguration class to IpManager for specifying
IP information in IpManager ProvisioningConfiguration at IpManager
startup.

At the moment this InitialConfiguration is not used, but is validated in
startProvsiioning if ProvisioningConfiguration includes one. It will be
integrated into IpManager IP provisioning logic in follow-up patches.

This patch also includes an example of data driven unit tests using a
table of test case. The highlights of this methodology are:
  1) easy extensibility for new test case,
  2) rich and informative error messages,
Unfortunately Java support for inlined data structure literals is poor
and some companion static methods for data generation are required for
enabling this methodology.

Bug: 62988545
Test: added new test in FrameworksNetTests,
      $ runtest frameworks-net
      $ runtest frameworks-wifi

Change-Id: I060b02603af7d73a6407df89344bf0c000574af2