Add inDrops support

### Description of feature Requested [here](https://github.com/nf-core/scrnaseq/issues/394#issuecomment-2474528363) and [here](https://nfcore.slack.com/archives/CHN5BV5DW/p1779466364172599). Currently, it is only possible to provide two FASTQ files - inDrops requires four of them.