Add argument for Guppy "chunks_per_runner"

[mshamash]

In testing buttery-eel with some BLOW5 data for basecalling, I realized that there is no "--chunks_per_runner" argument that could be set and passed through to Guppy. Is this something that could be easily added to a future release? I had originally tuned Guppy performance with the chunks_per_runner parameter, as opposed to changing chunk_size or max_queued_reads, and being able to set that to the same as my previous runs would allow for direct comparison of basecalling times between buttery-eel and Guppy. On a related note, is basecalling with buttery-eel using BLOW5 expected to be quicker than native Guppy/FAST5?

Thanks!