Initialize docs and hello display

src/main.cpp

@@ -0,0 +1,18 @@
+#include <Arduino.h>
+#include <U8g2lib.h>
+#include <Wire.h>
+
+// SH1106 128x64 OLED over hardware I2C, rotated 180 degrees for flipped mounting.
+U8G2_SH1106_128X64_NONAME_F_HW_I2C display(U8G2_R2, U8X8_PIN_NONE);
+
+void setup() {
+  display.begin();
+  display.clearBuffer();
+  display.setFont(u8g2_font_ncenB08_tr);
+  display.drawStr(18, 32, "Hello, world!");
+  display.sendBuffer();
+}
+
+void loop() {
+  delay(1000);
+}