Move in-house pods' test to AlphaWalletTests/modules/<pod>/

eg. AlphaWalletTests/modules/AlphaWalletAddress/

We could also add tests directly to each pod and those would be able to test the internals of the pods, but Cocoapods would generate them as separate targets. Adding them directly to the app is more convenient and reliable for us, but we'll only be able to test the public interface, which is good enough.