Check if running offline

This pipeline won't work in offline situations because it needs to download metadata and fastq files from the web. We should probably add a check/warning/fail to make sure that there is an internet connection when running. This would have to factor in situations where login nodes could have an internet connection but the nodes on the cluster may be offline. We should be able to add try/catch logic to the bin/sra_ids_to_runinfo.py script to detect this or maybe we just write a separate module for this that can be re-used if required as this will only ever by run once at the beginning of the workflow with almost zero resources.

Start with bin/sra_ids_to_runinfo.py and trace where metadata and FASTQ downloads begin. Run the workflow in an environment where login and cluster nodes differ in internet access; done means the pipeline detects unavailable connectivity on the execution nodes and gives a clear warning or failure before downloads begin.