Separate defaults for different planemo use cases

I made a few small PRs recently for new planemo options we need for running SARS-CoV-2 workflows: #1156, #1157, #1158.

It occurred to me that for different use-cases it doesn't necessarily make sense to have a single set of defaults for these and the already existing options, currently defined in the `options.py` file. Instead, `planemo run` vs. `planemo test`, as well as local vs. external galaxies, should have separate sets of default options. Not sure of the best way to implement this though,