Move NetworkManagementService into com.android.server.net

Move NetworkManagementService and NetworkManagementInternal from the
com.android.server package to com.android.server.net. Update
TEST_MAPPING to include NetworkManagementServiceTest in presubmit.

Bug: 259341026
Test: atest (triggering TEST_MAPPING execution)
Change-Id: Ibdff9c19c264ff54b9039e1f0aa4186641d5b302
6 files changed