Contrast -> Brightness

As it makes a little more sense in a 1 bit display

source/Core/Threads/GUIThread.cpp

@@ -799,6 +799,8 @@ void startGUITask(void const *argument) {
   prepareTranslations();
 
   OLED::initialize(); // start up the LCD
+  OLED::setBrightness(getSettingValue(SettingsOptions::OLEDBrightness));
+  OLED::setInverseDisplay(getSettingValue(SettingsOptions::OLEDInversion));
 
   uint8_t tempWarningState       = 0;
   bool    buttonLockout          = false;