* BIG refactor: 'board' and 'radio' objects now defined in 'target.h/.cpp'

* mesh::RTCClock class moved to MeshCore.h

variants/heltec_v3/platformio.ini

@@ -3,6 +3,7 @@ extends = esp32_base
 board = esp32-s3-devkitc-1
 build_flags =
   ${esp32_base.build_flags}
+  -I variants/heltec_v3
   -D HELTEC_LORA_V3
   -D RADIO_CLASS=CustomSX1262
   -D WRAPPER_CLASS=CustomSX1262Wrapper
@@ -16,6 +17,7 @@ build_flags =
   -D SX126X_CURRENT_LIMIT=130.0f  ; for best TX power!
   -D SX126X_RX_BOOSTED_GAIN=1
 build_src_filter = ${esp32_base.build_src_filter}
+  +<../variants/heltec_v3>
 lib_deps =
   ${esp32_base.lib_deps}
   adafruit/Adafruit SSD1306 @ ^2.5.13