Add routine to catch missing input data on filesystem

[riasc]

Missing input data causes:

MissingInputException in rule fastqc_forward in file /projects/b1171/sej9799/GBM_analysis/ScanNeo2/workflow/rules/preproc.smk, line 35:
Missing input files for rule fastqc_forward:
output: results/SRR8281248/rnaseq/qualitycontrol/rna_tumor_R1_fastqc_raw.html, results/SRR8281248/rnaseq/qualitycontrol/rna_tumor_R1_fastqc_raw.zip
wildcards: sample=SRR8281248, seqtype=rnaseq, group=rna_tumor
affected files:
../GBM/SRR8281248_1.fastq

Should be caught differently