JOSS Review - fdmr::retrieve_tutorial_data should not modify the home directory

[wcjochem]

Is your feature request related to a problem? Please describe.
fdmr::retrieve_tutorial_data() should not modify my home directory and I should have an option to choose where data should be downloaded.

Describe the solution you'd like
I think there should be an argument to the function to specify the download location, and the default download location should be the temporary directory.

Describe alternatives you've considered

Additional context
If you have aspirations for this package to go to CRAN then it cannot write anywhere except for R's temporary directory by default.

openjournals/joss-reviews#7047