Sets the RSPACE_API_URL environment variable to the provided RSpace API URL.
The RSpace API URL is likely the URL of your RSpace instance followed by api/v1.
Details
This will only set the environment variable for the current session,
to set it permanently, add RSPACE_API_URL=<your_api_url_here> to your .Renviron file,
for example, using usethis::edit_r_environ().