read and manage battery voltage

[cosmicpsyop]

Created and integrated a BatteryMonitor class formalizing what was used to test with T-HMI for general use.
1/ not really satisfied with the normalization of battery level based on voltage. charges to 100% unplug drops to 70%
2/ prototype temporary battery level on upper left for testing adding this to any screen layout.

#ifdef BATTERY_MONITOR_ENABLE
void printBatteryLevel()
{
  // Print Battery Level
  float batteryLevel = batteryMonitor.calculateBatteryLevel();

  // Convert float to string for rendering
  char batteryLevelStr[10];  // Adjust the size based on how many decimal places you need
  sprintf(batteryLevelStr, "%.0f", batteryLevel);  // Format float to string with 2 decimal places

  render.setFontSize(12);
  render.drawString(batteryLevelStr, 10/*210*/, 1,  TFT_WHITE/*0xDEDB*/);  // Use formatted string
}
#endif

3/ need help with background bmp graphics adjustments

See this video>> for how it works with lower screen and battery

#465