Implement ConnectivityStateMetrics sample

framework/src/android/net/NetworkCapabilities.java

.../com/android/metrics/ConnectivitySampleMetricsHelper.java

service/src/com/android/server/ConnectivityService.java

service/src/com/android/server/connectivity/FullScore.java

...src/com/android/server/connectivity/NetworkAgentInfo.java

...java/com/android/metrics/ConnectivitySampleMetricsTest.kt

...unit/java/com/android/server/ConnectivityServiceTest.java