Create ServiceConnectivityResources

Create the ServiceConnectivityResources package, which contains
resources Connectivity unbundled from platform resources.

Migrate the first few resources from ConnectivityService that have no
RRO in AOSP. To avoid boot time impact, avoid loading the resources in
the ConnectivityService constructor.

Bug: 182125649
Test: atest FrameworksNetTests
Change-Id: I77ac6f4303c54acc96f16e18ef02add30298ff3d