feat: add display of counter value

lib/GazDisplay/GazDisplay.h

@@ -0,0 +1,21 @@
+#pragma once
+
+#include <Wire.h>
+#include <Adafruit_GFX.h>
+#include <Adafruit_SSD1306.h>
+
+#define OLED_SDA 21
+#define OLED_SCL 22
+#define OLED_RST -1
+
+#define SCREEN_WIDTH 128
+#define SCREEN_HEIGHT 64
+
+enum class DisplayError : int16_t {
+    OK           =  0,
+    INIT_FAILED  = -1
+};
+
+void displayInit();
+void displayGasIndex(uint32_t pulses);
+