feat(android): use newer APIs for battery level/status properties

[m1ga]

The current implementation of the battery level/state properties are returning the stored values from the BroadcastReceiver. Android introduced a way to query the value using the BatteryManager starting in 21 (level) and 26 (state).

Android docs:
https://developer.android.com/reference/android/os/BatteryManager.html#BATTERY_PROPERTY_STATUS
https://developer.android.com/reference/android/os/BatteryManager.html#BATTERY_PROPERTY_CAPACITY

Currently the initial value is -1 and if the receiver wasn't called yet (e.g. timing or it was somehow removed) it won't update the values.

The new way should still return a fresh value because it reads it when your fetch the property.

Update
Battery level: since 21 is the current minSDK I removed the if and just use the new value.

Test:

var win = Ti.UI.createWindow();
win.open();

win.addEventListener("open", function() {
	console.log("Level", Titanium.Platform.batteryLevel);
	console.log("Status", Titanium.Platform.batteryState);
})