Add a listToSamplesheet function

[nvnieuwk]

This function will basically do the reverse of samplesheetToList. Taking in a list, output file name and a schema file.

It will validate the list and convert it to the samplesheet file.

[nvnieuwk]

Some roadblocks were encountered while developing this function (mainly about files in work directories). We don't want to have the paths to the work directory in a samplesheet, but there is no decent method to fetch the path to the published file (AFAIK). Putting this issue on hold for now

It might also be a better idea to simply start using the index file creation in the new workflow output definitions in Nextflow itself. These don't have any validation though.

[nvnieuwk]

All work on this function can be found in this branch: https://github.com/nextflow-io/nf-schema/tree/listToSamplesheet