Remove translators

[KenSakayori]

This commit removes all the translators, which translates an input of some program verification problem to a hflz formula.
Removing this may be controversial, but here are the reasons to do so

1. Translators are not the core functionality of MuHFL. Having these tools inside this repository just makes it hard to maintain this project.
2. No one really knows how to use them. It is not documented at all, and Tanahashi-san already graduated.
3. Using MoCHi's frontend would give us a better converter. And it is quite stupid to maintain something like a parser of a subset of an OCaml program, which already exists in MoCHi.

[KenSakayori]

I merged this because no one was against it.
We may restore these features in the future.