FastQC metrics missing from RDS and multiqc folder

[epruesse]

reported by @bethsecor

[epruesse]

It appears that the multiqc_fastqc.txt file that we have been using is no longer generated by MultiQC. Instead, it generates a gigantic JSON file that holds all the data. It'll be easier to parse, but it means I have to rewrite the part in the RDS generation that creates the QC tables.