Adding Particle System (port from AC)

- port from AC
- also adding hardware random functions

wled00/util.cpp

@@ -653,3 +653,18 @@ char *cleanUpName(char *in) {
   
   return(in);
 }
+
+// 32 bit hardware random number generator, inlining uses more code, use hw_random16() if speed is critical (see fcn_declare.h)
+uint32_t hw_random(uint32_t upperlimit) {
+  uint32_t rnd = hw_random();
+  uint64_t scaled = uint64_t(rnd) * uint64_t(upperlimit);
+  return scaled >> 32;
+}
+
+int32_t hw_random(int32_t lowerlimit, int32_t upperlimit) {
+  if(lowerlimit >= upperlimit) {
+    return lowerlimit;
+  }
+  uint32_t diff = upperlimit - lowerlimit;
+  return hw_random(diff) + lowerlimit;
+}