Atlas and template resources

[akhanf]

Currently we have zip files for each, and so snakemake tracks the folder that contains the files. This led to some awkward workarounds (defining the atlas dir as an input, but the files themselves as parameters). Ultimately it would be better to have the individual files tracked in the workflow, both for error checking, and for future maintenance (eg adding more atlas/template files), so marking this as a nice to have feature for v2.0. Perhaps could use some automation to help grab urls, or use a s3 bucket where the file path can be part of the url..