Feature request: Add tool to change scorer alphabet

[JRMeyer]

Is your feature request related to a problem? Please describe.
I have a scorer trained for language X, and it was compiled with alphabet Y. Now I have a new acoustic model (*.pbmm file) which was trained with alphabet Z. I'd like to use my old scorer on new acoustic model, but because the alphabets are not exactly the same, the models are incompatible. I would have to retrain one of the models with the compatible alphabet to use models together. This is burdensome because of the need for data and compute resources.

Describe the solution you'd like
I'd like to be able to specify a new alphabet, and re-export the scorer to be compatible with my acoustic model.

Describe alternatives you've considered
Re-train the language model and re-export the scorer.

Additional context
This is a common problem for sharing models.