[fud2] Support parametric states

Parametric states may increase code reuse and reduce similar states in fud2's scripts (e.g. `calyx` and `calyx-noverify`). Write ups with some ideas about what this could mean can be found [here](https://github.com/calyxir/project/blob/main/notes/fud2-next.md#parametric-states) and [here](https://github.com/calyxir/project/blob/main/notes/fud2-parametric-states.md).