Add support for printers with inverted fan pins (#13362)

Add support for printers with inverted fan pins by adding `#define FAN_INVERTING 1` to `Configuration_adv.h` and modifying the fan write macros.

Marlin/src/inc/Conditionals_post.h

 /**
  * Up to 3 PWM fans
  */
+#ifndef FAN_INVERTING
+  #define FAN_INVERTING false
+#endif
+
 #if HAS_FAN2
   #define FAN_COUNT 3
 #elif HAS_FAN1
 #endif
 
 #if HAS_FAN0
-  #define WRITE_FAN(v) WRITE(FAN_PIN, v)
+  #define WRITE_FAN(v) WRITE(FAN_PIN, (v) ^ FAN_INVERTING)
   #define WRITE_FAN0(v) WRITE_FAN(v)
 #endif
 #if HAS_FAN1
-  #define WRITE_FAN1(v) WRITE(FAN1_PIN, v)
+  #define WRITE_FAN1(v) WRITE(FAN1_PIN, (v) ^ FAN_INVERTING)
 #endif
 #if HAS_FAN2
-  #define WRITE_FAN2(v) WRITE(FAN2_PIN, v)
+  #define WRITE_FAN2(v) WRITE(FAN2_PIN, (v) ^ FAN_INVERTING)
 #endif
 #define WRITE_FAN_N(n, v) WRITE_FAN##n(v)