DCC/MQTT Light Decoder U2.1 Modular

Required libraries:
- ProjectUNION Core 0.3.1
- ProjectUNION MQTT 0.3.1
- ProjectUNION DCC 0.3.0
- PubSubClient
- NmraDcc
- FastLED
- Adafruit GFX
- Adafruit SSD1306

Test:
1. Compile and note program and RAM size.
2. Upload and test WiFi/web configuration.
3. Test MQTT connection and commands.
4. Test DCC commands.
5. Test OLED.
6. Test all five WS2812 outputs and effects.
7. Test random-house mode.
8. Test OTA.
