Add tasks for all the new languages

Task/Josephus-problem/Sidef/josephus-problem-1.sidef

@@ -0,0 +1,7 @@
+func josephus(n, k) {
+    var prisoners = @^n
+    while (prisoners.len > 1) {
+        prisoners.rotate!(k - 1).shift
+    }
+    return prisoners[0]
+}

Task/Josephus-problem/Sidef/josephus-problem-2.sidef

@@ -0,0 +1,3 @@
+func josephus(n, k) {
+    n == 1 ? 0 : ((__FUNC__(n-1, k) + k) % n)
+};

Task/Josephus-problem/Sidef/josephus-problem-3.sidef

@@ -0,0 +1,2 @@
+var survivor = josephus(41, 3);
+say "Prisoner #{survivor} survived.";