[NEW] Use Touch_Interrupt pin

[AlexanderTonn]

 :rocket: Please describe your feature request

• touch IRQ pin is already wired and have to be programmed
• currently the touch detection is looped in each cycle. This costs a lot of cpu load
• touch IRQ is reducing the CPU load, because the touch code is only executed if touch is pressed

 :pencil2: Describe the solution you'd like

 :pushpin: Describe alternatives you've considered

• A clear and concise description of any alternative solutions or features you've considered.

Additional context

• Add any other context or screenshots about the feature request here.

[AlexanderTonn]

Touch IRQ will not work for some reason with this code. Wiring is definitely correct

constexpr static uint8_t TOUCH_IRQ = 2; // Touch Interrupt
constexpr static uint8_t TOUCH_CS = 3; // Touch Chip Select

Adafruit_ILI9341 tft = Adafruit_ILI9341(TFT_CS, TFT_DC);
XPT2046_Touchscreen touch(TOUCH_CS, TOUCH_IRQ);

  // Detecting touch
  if (touch.tirqTouched())
  {
    if(touch.touched())
    {
    TS_Point touchPoint = touch.getPoint();
    touchPoint.x = map(touchPoint.x, TOUCH_X_MIN, TOUCH_X_MAX, tft.width(), 0);
    touchPoint.y = map(touchPoint.y, TOUCH_Y_MIN, TOUCH_Y_MAX, 0, tft.height());
    Serial.print("(x: ");
    Serial.print(touchPoint.x);
    Serial.print(")");
    Serial.print("(y: ");
    Serial.print(touchPoint.y);
    Serial.println(")");
    Serial.print("Touch Pressure: ");
    Serial.println(touchPoint.z);

    detectTouch(touchPoint.x, touchPoint.y, byPageId);
    }
  }