Default pin remap for wESP32 (#2508)

* Add default pin mapping for Serial1 and Serial2

* Default pin remap on wESP32

Improved default pin mapping for I2C0 and UART1 to avoid issues
with programming.
SDA0 was on IO2 but IO2 needs to be pulled low on reset to enable
serial programming, which conflicts with I2C pull-ups.
RX1 was on IO12, idle UART level is high which conflicts with
IO12 needing to be low on reset to select correct 3.3V flash
voltage.
New mappings:
SDA0 on IO15
RX1 on IO13
TX1 on IO12

variants/wesp32/pins_arduino.h

@@ -11,8 +11,8 @@
 #define digitalPinToInterrupt(p)    (((p)<40)?(p):-1)
 #define digitalPinHasPWM(p)         (p < 34)
 
-#define TX1   13
-#define RX1   12
+#define TX1   12
+#define RX1   13
 #define TX2   33
 #define RX2   39
 
@@ -20,7 +20,7 @@ static const uint8_t TX = 1;
 static const uint8_t RX = 3;
 
 static const uint8_t SCL = 4;
-static const uint8_t SDA = 2;
+static const uint8_t SDA = 15;
 
 static const uint8_t SS    = 5;
 static const uint8_t MOSI  = 23;