Add power test cases

example/advanced/Power_Management_Tests/Battery_discharge_logging/Battery_discharge_logging.ino

@@ -0,0 +1,29 @@
+#include "Dezibot.h"
+// Output CSV-Data about the power state on secondary UART mapped to bottom
+// header
+
+// Using alternate Serial pins to not be powered by the USB port
+#define RXD_HEADER 16
+#define TXD_HEADER 17
+
+Dezibot dezibot = Dezibot();
+void setup() {
+  // put your setup code here, to run once:
+  dezibot.begin();
+  Serial1.begin(9600, SERIAL_8N1, RXD_HEADER, TXD_HEADER);
+  Serial1.printf("Timestamp (ms),Current (mA),charge (%%),charge (C),voltage (V),isUSBPowered,isBatteryPowered,isBatteryCharging,isBatteryDischarging,isBatteryFullyCharged\r\n");
+}
+
+void loop() {
+  Serial1.printf("%d,%f,%f,%f,%f,%d,%d,%d,%d,%d\r\n",
+                 millis(),
+                 dezibot.power.getCurrentCurrent(),
+                 dezibot.power.getBatteryChargePercent(),
+                 dezibot.power.getBatteryChargeCoulombs(),
+                 dezibot.power.getBatteryVoltage(),
+                 dezibot.power.isUSBPowered(), dezibot.power.isBatteryPowered(),
+                 dezibot.power.isBatteryCharging(),
+                 dezibot.power.isBatteryDischarging(),
+                 dezibot.power.isBatteryFullyCharged());
+  sleep(1);
+}