largefiles: drop --cache-largefiles again This goes a step further than d69585a5c5c0 and backs out the unreleased --cache-largefiles option. The same can be achieved with --lfrev heads(pulled()) and we shouldn't introduce unnecessary command line options.

largefiles: introduce pulled() revset expression for use in --lfrev This provides a general way to do what already can be done with --all-largefiles and --cache-largefiles.

largefiles: introduce pull --lfrev option The revset will be evaluated after the changesets has been pulled, and missing largefiles from matching revisions will be pulled to the local caches. This in combination with revsets will make it possible to specify different strategies for pulling largefiles. The revset expressions used for this option might be quite complex and will probably be most useful from scripts or an alias ... but less complicated than configuring hooks.