Exporting Trainined Model

Hi, thanks for the wonderful project!

I want to train my own model, but before that to get an idea of the existing functionality I tried running the original code without any changes.

### Steps

So I first cloned this repo inside `kaldi/egs/

then I ran the command:

```
cd kaldi/tools/; make; cd ../src; ./configure; make
```

Then:
```
cd kaldi/egs/vos-api/training
./run.sh
```

The model is trained, but I am not sure how to export it.

I see that: [model structure](https://alphacephei.com/vosk/models#model-structure) refers to arranging files in a certain format, but the same files are present in multiple places

eg: `final.mdl`

it is present in `mono` `mono_ali` `chain/tdnn` etc

In the issue here: https://github.com/alphacep/vosk-api/issues/41#issuecomment-1108807005 You mentioned that model is exported in `exp/chain/tdnn` but not all the files are present here.

It would be great if you can explain to me which files at which location we have to use. Also, do we have some script for the same?