singularity: update configs to use docker hub and specified cacheDir

src/nf_modules/hisat2/indexing.config

src/nf_modules/hisat2/mapping_paired.config

src/nf_modules/hisat2/mapping_single.config

src/nf_modules/htseq/htseq.config

src/nf_modules/kallisto/indexing.config

src/nf_modules/kallisto/mapping_paired.config

src/nf_modules/kallisto/mapping_single.config

src/nf_modules/macs2/peak_calling.config

src/nf_modules/multiqc/multiqc_paired.config

src/nf_modules/multiqc/multiqc_single.config

src/nf_modules/music/peak_calling_single.config

src/nf_modules/rsem/indexing.config

src/nf_modules/rsem/quantification_paired.config

src/nf_modules/rsem/quantification_single.config

src/nf_modules/sambamba/index_bams.config

src/nf_modules/sambamba/sort_bams.config

src/nf_modules/sambamba/split_bams.config

src/nf_modules/samblaster/dedup_sams.config

src/nf_modules/samtools/filter_bams.config

src/nf_modules/samtools/index_bams.config