Add tasks for all the new languages

Task/Narcissistic-decimal-number/Sidef/narcissistic-decimal-number.sidef

@@ -0,0 +1,11 @@
+func is_narcissistic(n) {
+    n.digits »**» n.len -> sum(0) == n
+}
+
+var count = 0
+for i in (0..^Inf) {
+    if (is_narcissistic(i)) {
+        say "#{++count}\t#{i}"
+        break if (count == 25)
+    }
+}