Centralize nsd associated files

Move all nsd associated files include framework, service and test
to package/Nsd first. After clear all hidden API dependencies, we
can easily migrate these files into connectivity mainline module.

Bug: 206893064
Test: atest FrameworksNetTests CtsNetTestCases
Change-Id: Id26f471a10fe7882e31ccc2dbb73219461f00dbd
18 files changed