Provide json file from gene panel store to anno-targets in annopipe.nf

Today we provide all files for a gene panel from the genepanel store, except the gene panel JSON-file, which is the basis for all the other files. Providing the JSON-file will allow for eventually removing the environment variables REPORT_CONFIG, GP_NAME, GP_VERSION, TRANSCRIPTS, PHENOTYPES, and EXON_REGIONS, since these can then be deduced from the JSON-file downstream (in anno-targets).