Add rand.init_as_system to allow for system-level based random number generation

core/math/rand/system_windows.odin

@@ -0,0 +1,12 @@
+package rand
+
+import win32 "core:sys/windows"
+
+_system_random :: proc() -> u32 {
+	value: u32
+	status := win32.BCryptGenRandom(nil, ([^]u8)(&value), 4, win32.BCRYPT_USE_SYSTEM_PREFERRED_RNG)
+	if status < 0 {
+		panic("BCryptGenRandom failed")
+	}
+	return value
+}