Add tasks for all the new languages

Task/Probabilistic-choice/Nim/probabilistic-choice.nim

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+import tables, math, strutils, times
+
+const
+   num_trials = 1000000
+   precsn     = 6
+
+var start = cpuTime()
+
+var probs = initTable[string,float](16)
+probs.add("aleph",  1/5.0)
+probs.add("beth",   1/6.0)
+probs.add("gimel",  1/7.0)
+probs.add("daleth", 1/8.0)
+probs.add("he",     1/9.0)
+probs.add("waw",    1/10.0)
+probs.add("zayin",  1/11.0)
+probs.add("heth",   1759/27720)
+
+var samples = initTable[string,int](16)
+for i, j in pairs(probs):
+    samples.add(i,0)
+
+randomize()
+for i in 1 .. num_trials:
+    var z = random(1.0)
+
+    for j,k in pairs(probs):
+        if z < probs[j]:
+            samples[j] = samples[j] + 1
+            break
+        else:
+             z = z - probs[j]
+
+var s1, s2: float
+
+echo("Item  ","\t","Target  ","\t","Results  ","\t","Difference")
+echo("====  ","\t","======  ","\t","=======  ","\t","==========")
+for i, j in pairs(probs):
+    s1 += samples[i]/num_trials*100.0
+    s2 += probs[i]*100.0
+    echo( i,
+             "\t", formatFloat(probs[i],ffDecimal,precsn),
+             "\t", formatFloat(samples[i]/num_trials,ffDecimal,precsn),
+             "\t", formatFloat(100.0*(1.0-(samples[i]/num_trials)/probs[i]),ffDecimal,precsn),"%")
+echo("======","\t","======= ","\t","======== ")
+echo("Total:","\t",formatFloat(s2,ffDecimal,2),"  \t",formatFloat(s1,ffDecimal,2))
+echo("\n",formatFloat(cpuTime()-start,ffDecimal,2)," secs")