[enhancement] do .yaml config parsing and puting into channels in groovy instead of python

### Description of feature

currently .yaml config parsing/splitting into multiple yamls happens in a python process, we would like this to happen in groovy for multiple reasons : 
- python programs do not use .yaml files, this is specific to the nextflow pipeline 
- would not require stimlus-py container to split .yaml files 
- more in line with nf-core/nextflow philosophy 