Add nf-schema

[ctuni]

[Emeerdink]

nf-schema provides a way to validate input parameters, such as the sample sheet and other required files, ensuring they are correctly defined before the pipeline runs. By specifying these parameters in nextflow_schema.json, we can enforce validation and improve error handling.

We need to ensure that all required input parameters are properly defined in nextflow_schema.json, preventing issues caused by missing or incorrect files.

Reference Example nf-core/rnaseq/nextflow_schema.json

[ctuni]

The samplesheet handling is done now using nf-schema.

As we add input params (gtf, fasta, etc), we can also validate them using nf-schema