Add tasks for all the new languages

Task/Multifactorial/Nim/multifactorial.nim

@@ -0,0 +1,16 @@
+# Recursive
+proc multifact(n, deg): int =
+  result = (if n <= deg: n else: n * multifact(n - deg, deg))
+
+# Iterative
+proc multifactI(n, deg): int =
+  result = n
+  var n = n
+  while n >= deg + 1:
+    result *= n - deg
+    n -= deg
+
+for i in 1..5:
+  stdout.write "\nDegree ", i, ": "
+  for j in 1..10:
+    stdout.write multifactI(j, i), " "