bbmap_bbsplit input file logic requires revision

[tverbeiren]

The component is defined in BioBox and can do two things:

Outputs reads to a file for the reference they best match, with multiple options for dealing with ambiguous mappings.

To index:     bbsplit.sh build=<1> ref_x=<reference fasta> ref_y=<another reference fasta>
To map:       bbsplit.sh build=<1> in=<reads> out_x=<output file> out_y=<another output file>

In the present case we want to generate an index. There is an issue, however, with the way the parameters are passed. Moreover, extra validation should occur to cover the dependencies between different arguments/parameters.

The option skip_bbsplit has been disabled until this issue has been resolved.