Unicycler should allow also long read and hybrid assembly

[d4straub]

Is your feature request related to a problem? Please describe

The Unicycler module only allows short read assembly but not long read or hybrid assembly.

Describe the solution you'd like

A module that does it all, like in nf-core/bacass.

This is also mentioned in nf-core/bacass#61

Describe the solution you'd like

Instead of

    input:
    tuple val(meta), path(reads)

and
def input_reads = meta.single_end ? "-s $reads" : "-1 ${reads[0]} -2 ${reads[1]}"

one could do

    input:
    tuple val(meta), path(shortreads), path(longreads)

and

    if(shortreads){
        def short_reads = meta.single_end ? "-s $shortreads" : "-1 ${shortreads[0]} -2 ${shortreads[1]}"
    } else { def short_reads =  "" }
    def long_reads = longreads ? "-l $longreads" : ""
    def input_reads = "$short_reads $long_reads"

where [] would be given into the input channel when no respective reads exist.

Describe alternatives you've considered

Alternatively, this could be as well solved in 3 different modules, sich as Unicycler_short, Unicycler_long & Unicycler_hybrid. I am not sure whats the better way.

Additional context