Redirect the genomes staged in sourmash subworkflow to a directory

[danilodileo]

Description of feature

As it works now, the staged genomes needs to be called again every time we resume the pipeline. Despite it is not a bug and the pipeline works, it takes time to reach the point where all genomes are staged. So it would be nice that once selected, the genomes are stored in a directory that can be called instead of re-staging the genomes.