Add tasks for all the new languages

Task/Fast-Fourier-transform/Nim/fast-fourier-transform.nim

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+import math, complex, strutils
+
+proc toComplex(x: float): TComplex = result.re = x
+proc toComplex(x: TComplex): TComplex = x
+
+# Works with floats and complex numbers as input
+proc fft[T](x: openarray[T]): seq[TComplex] =
+  let n = x.len
+  result = newSeq[TComplex]()
+  if n <= 1:
+    for v in x: result.add toComplex(v)
+    return
+  var evens, odds = newSeq[T]()
+  for i, v in x:
+    if i mod 2 == 0: evens.add v
+    else: odds.add v
+  var (even, odd) = (fft(evens), fft(odds))
+
+  for k in 0 .. < n div 2:
+    result.add(even[k] + exp((0.0, -2*pi*float(k)/float(n))) * odd[k])
+
+  for k in 0 .. < n div 2:
+    result.add(even[k] - exp((0.0, -2*pi*float(k)/float(n))) * odd[k])
+
+for i in fft(@[1.0, 1.0, 1.0, 1.0, 0.0, 0.0, 0.0, 0.0]):
+  echo formatFloat(abs(i), ffDecimal, 3)