Widget idea: BLE Battery Service

Hi. I was thinking it would be nice if the Bangle could advertise it's battery level (so Home Assistant can remind to charge it, for example).

Does anything like this exist? Is a widget the right way to do it? Something like this works for me.

(() => {
  function advertiseBattery() {
    NRF.setAdvertising([
      {0x180F : [E.getBattery()]},
    ]);
  }
  
  setInterval(advertiseBattery, 60 * 1000);
  advertiseBattery();
  
  // add your widget
  WIDGETS["ble_battery_service"]={
    area:"tl", // tl (top left), tr (top right), bl (bottom left), br (bottom right)
    width: 0, // how wide is the widget? You can change this and call Bangle.drawWidgets() to re-layout
    draw: function() {} // called to draw the widget
  };
})()

I'll open a PR if this is sensible. Thanks.