Initial commit: Simple Sensor firmware for Heltec T114 with BME280

- MeshCore-based Simple Sensor firmware
- Heltec T114 without display
- BME280 sensor support (temp/humidity/pressure)
- Radio: 868.856018 MHz, SF7, BW62.5 kHz, CR4/7
- 2-byte path hash
- PlatformIO project

variants/keepteen_lt1/KeepteenLT1Board.cpp

@@ -0,0 +1,17 @@
+#include <Arduino.h>
+#include <Wire.h>
+
+#include "KeepteenLT1Board.h"
+
+void KeepteenLT1Board::begin() {    
+    NRF52Board::begin();
+    btn_prev_state = HIGH;
+  
+    pinMode(PIN_VBAT_READ, INPUT);
+
+    #if defined(PIN_BOARD_SDA) && defined(PIN_BOARD_SCL)
+      Wire.setPins(PIN_BOARD_SDA, PIN_BOARD_SCL);
+    #endif
+    
+    Wire.begin();
+}