Get `location` argument working for PyPi installers

[robynstuart]

Either before or after merging #149, need to figure out how to generalize this workflow for Pypi installers, as it's currently set up for GH installers

[robynstuart]

From @RomeshA on Slack: I think the best option might be to use https://pypi.org/project/platformdirs/ or similar to store the files in a standard system user directory. The alternative would be to base it on the user's current directory but a typical application has scripts in different folders and gets executed from different places, so users could end up with multiple copies etc. and it would be a bit fragile. But I think we could do it so that it only uses the platform directory if it was not installed via git, so otherwise the files show up in the usual place (and that would also facilitate usage on various clusters too). Do you think that would be workable?