Refactor SystemUI and add function in settingslib for service state

To make behavior consistent in the long run and refactor the code
into settingslib and call it from both Settings and SystemUI.

Bug: 110973964
Test: run testcase as below:
1. frameworks/base/packages/SettingsLib: -> ALL PASS
make RunSettingsLibRoboTests -j40
2. frameworks/base/packages/SystemUI: -> ALL PASS
atest frameworks/base/packages/SystemUI/tests/src/com/android/systemui
/statusbar/policy/NetworkControllerSignalTest.java

Change-Id: Ie8899dd5398a503b861557c222bbd93bd2049d10