Add progress bar

[Aeilert]

@ohjakobsen: What do you think of adding a progress bar to some (or all) of the exported functions? E.g. querying several hundred entities from ER takes quite some time (partially due to the current throttling limit), and users might wonder how much time is left. Or even if someething is wrong.

[ohjakobsen]

For long running processes, this could be a good idea. We could check the length of the input, and provide a progress bar for all queries of a certain length. But we should make sure that this only runs in interactive environments, and that it can be turned off if needed, i.e. for programatic use cases (it will also wreck havoc in the console in a Shiny context).

[Aeilert]

This could possibly be as simple as adding httr2::req_progress() to send_query(). See recent blog: https://www.tidyverse.org/blog/2023/11/httr2-1-0-0/#control-the-request-process.

Maybe something for @joasand to look at. cc: @ohjakobsen