Default RF_RECEIVER_GPIO for NodeMcu should be changed

[bartek75]

Describe the bug
Default RF_RECEIVER_GPIO is set to 0 (D3 on nodemcu), this setting prevents nodemcu to boot as D3 is used to enable flash mode on nodemcu

To Reproduce
Steps to reproduce the behavior:

1. Flash nodemcu with default firmware
2. Restart nodemcu
3. it does not start (one blink with led , then nothing)

Expected behavior
Normal start after restart

Environment (please complete the following information):

• OpenMQTTGateway version used v1.8.1