pkgdown website for setup_package()

[ElsLommelen]

When using create_package(), a pkgdown website in INBO style is automatically created. When using setup_package() on an existing package, this is unfortunately not the case. Some packages may indeed already have a website when applying setup_package(), but if this is not the case, it would be nice to have an option to add it. (It could even be nice to have an opportunity to only add a pkgdown site in INBO style to a package, but this is obviously not the goal of the checklist package. ;-) )