Battery and next alarm sensor improvements

[dshokouhi]

Battery level sensor:

• Fix battery level icon so it matches battery state. This will align with the iOS app and fixes Battery Level Sensor Icon not updated when charging. #536

Battery state sensor:

• Add attribute for battery health
• Add intents for battery low and okay. Battery low triggers when the system alerts the user the battery is low. Okay triggers when it recovers from being low
• Add a second update when we receive a battery intent to update the charging state faster. As mentioned in Added ChargingBroadcastReceiver which can instantly update plugged in… #525 by @yoxjames without the battery changed intent the charging state won't fully update until the next sensor update. This is because the device is verifying the charging status. When we switch to battery intent the system sees several state updates which are a bit unnecessary. Waiting 5 seconds to update the state again ensures we not only detect the plug event instantly but also makes sure the state is as expected.

Next alarm sensor

• Add attribute for the package name that scheduled the alarm. Partially fixes: Next Alarm Filter #737