rm .demux and make sure that folders are gz

[antgonza]

We are currently generating/using the .demux file and not compressing the fna/fastq results. Removing the .demux and making sure to gz fna/fastq will save lots of storage.

cc: @wasade

[antgonza]

As part of the 052020 we will compress all fna/fastq currently in the system. Also, plugins and validators will only generate/consume gz versions of those formats. Going to close this issue for now.