- endpoint abstractions now share an interface `Abstraction`
- pkg endpoint now has a query facitilty (`ListAbstractions`) which is
used to find on-disk
- step holds and bookmarks
- replication cursors (v1, v2)
- last-received-holds
- the `zrepl holds list` command consumes endpoint.ListAbstractions
- the new `zrepl holds release-{all,stale}` commands can be used
to remove abstractions of package endpoint
Co-authored-by: InsanePrawn <insane.prawny@gmail.com>
supersedes #282fixes#280fixes#278