moving the half fat epi tests into the main half-fat test suite, as it is much faster now and doesnt need to be a discretionary task run

adding wheat_group and wheat_group_display args to depo - this will be used when we start running different strains dynamically. For now we are hard-coding to "PROD". The "PROD" will appear in filenames, but not the image titles

adding function to set test outdir as an environemnt variable - so you can change the default location, which is hard-coded

extracting functions to allow the ews job dir and the config dict to be created without needing to run the pipeline - allows epi fitting to retrieve these values if the peipeline has already run

making the running of epi plotting dependant on whether config had been provided. Modifying tests to stop using epi outputs which are no longer included

adding ability to set additional values to the run config from the command line args (if not already present in the config json)
modifying the epi processor to look for CalculationSpanDays in both the config json and the command line args, as preparation for use with the Epi fitting, which will pass calcspan as an arg