Merge pull request #4060 from DedeHai/0_15_bootdelay

boot-up delay to fix wifi not starting in some setups

use
`-D WLED_BOOTUPDELAY=500` (or some other delay you want, in milliseconds)
in platformio env definition to add 500ms of delay before hardware init.

wled00/wled.cpp

@@ -448,6 +448,9 @@ void WLED::setup()
   #ifdef ARDUINO_ARCH_ESP32
   pinMode(hardwareRX, INPUT_PULLDOWN); delay(1);        // suppress noise in case RX pin is floating (at low noise energy) - see issue #3128
   #endif
+  #ifdef WLED_BOOTUPDELAY
+  delay(WLED_BOOTUPDELAY); // delay to let voltage stabilize, helps with boot issues on some setups
+  #endif
   Serial.begin(115200);
   if (!Serial) delay(1000); // WLEDMM make sure that Serial has initalized