Create service-connectivity.jar

Create a new target service-connectivity to split
ConnectivityService from services.core.

Add ConnectivityServiceInitializer for initializing
ConnectivityService and add systemReady() in
ConnectivityManager so that SystemServer can call systemReady()
through ConnectivityManager which won't change current behavior.

Bug: 158268939
Test: make target-java, make host-java
      atest FrameworksNetIntegrationTests
      atest FrameworksNetTests
      make, device can boot,
      atest CtsStrictJavaPackagesTestCases
      wifi and mobile data work.
Change-Id: Ie732bfaf381404af0bb599ca2f421a96e7aa4257
diff --git a/services/Android.bp b/services/Android.bp
index 33205c0..8c9c487 100644
--- a/services/Android.bp
+++ b/services/Android.bp
@@ -92,6 +92,7 @@
         "services.voiceinteraction",
         "services.wifi",
         "service-blobstore",
+        "service-connectivity",
         "service-jobscheduler",
         "android.hidl.base-V1.0-java",
     ],