nf-core/tbanalyzer test dataset: downsampled Mycobacterium tuberculosis reads

Minimal test data for the nf-core/tbanalyzer pipeline (--mode mtbseq). Five Mycobacterium tuberculosis Illumina paired-end samples, each downsampled with seqtk to ~11x coverage of the H37Rv genome: two from the MTBseq-nf publication/pipeline (ENA accessions ERR553286 and ERR551038) and three from the MAGMA pipeline test set (SRA accessions SRR26331590, SRR26331595 and SRR26331599). Reads are named by their ENA/SRA run accession. Also includes test_samplesheet.csv and test_cohort.tsv wired for the pipeline test profiles. Intended only for continuous-integration / functional testing, not for biological interpretation.