Merge branch 'cc/lop-filter-auto'

"auto filter" logic for large-object promisor remote. * cc/lop-filter-auto: fetch-pack: wire up and enable auto filter logic promisor-remote: change promisor_remote_reply()'s signature promisor-remote: keep advertised filters in memory list-objects-filter-options: support 'auto' mode for --filter doc: fetch: document `--filter=<filter-spec>` option fetch: make filter_options local to cmd_fetch() clone: make filter_options local to cmd_clone() promisor-remote: allow a client to store fields promisor-remote: refactor initialising field lists