"Keep going" mode for renv::restore() and perhaps renv::install() #1109
Description
Follow-up to #746. A perhaps more ambitious variant of #1108.
When attempting renv::restore() from a large renv.lock file, the renv.config.install.transactional config already avoids a lot of repeated work. Ideally, a "keep going" mode, similar to make -k, would attempt to install all packages that can be installed (and even avoid erroring on download failures). The first restore() would then be a "best effort" install, following attempts would focus on installing packages that failed with the first attempt (in combination with renv.config.install.transactional).