Setup some tracing for ml_translatorLib

Currently figuring out what is happening internally in `ml_translatorLib` is pretty much impossible. It would be nice if there's some tracing setup. It should probably be implemented using the Listener api similar to how it's done in the HOL4's simplifier[1].

[1]https://github.com/HOL-Theorem-Prover/HOL/blob/6ee078177f8f5ff059b57fb0d9ba3b090df1d1b9/src/simp/src/Trace.sml