Allow to use a bundle zip for html template

[ColinFay]

some html templates are bundled as a zip so it might be interesting to be able to get them

[ilyaZar]

Note sure about what the expected behaviour is.

Do you mean adding a helper like so:

unzip_html_bundle <- function(from, to) {
   unzip(zipfile = from, exdir = to)
   # possible removing old .zip via
   unlink(from, recursive = TRUE)
   return(invisible(pth))
}

Then adding this to use_external_html_template (), use_internal_html_template () and add_html_template() with a flag e.g. use_html_bundle=TRUE/FALSE.

Re-using this helper then with other argument values passed down from these three versions?

Also there can be like some dozen templates inside inst/app/www so not sure if that's what is intended when downloading a whole bundled zip; one could prompt the user for a specific template to keep, removing the rest, but that could also be out of scope for this feature.

Happy to get on this, though, there is #1022 . If, by any chance #1022 is still relevant I'd happy to PR here after #1022 is merged (or closed).