Set membership test rewriting optimizer

[TristonianJones]

Translates expressions like a in [1, 2, 3] to a in {1: true, 2: true, 3: true}

The benefit of this change is that most of the set relationship operations over lists
are O(n) where n represents the number of elements in the list. The cel.OptOptimize
flag will perform a similar optimization at runtime; however, this optimizer performs
the optimization at compile time.