feat: add sample(list) and sample(list, count) methods to Random class with two sampling algorithms

test/random/sample_count_too_many.wren

@@ -0,0 +1,5 @@
+import "random" for Random
+
+var random = Random.new(12345)
+
+random.sample([1, 2, 3], 4) // expect runtime error: Not enough elements to sample.