Integrate Signal Threshold for 5G

1) Introduce default values for 5G Signal thresholds
2) Introduce parameter to control in 5G NR Signal Strength Level
3) Introduce SignalThresholdInfo to support Framework and HAL

Test: Treehugger
Bug: 135717625
Change-Id: I8a716e9fe445349a56bb33b6b8f581febb21552b