Now that we make the user/group name resolving available via userdb and
thus nss-systemd, we do not need the UID/GID resolving support in
nss-mymachines anymore. Let's drop it hence.
We keep the module around, since besides UID/GID resolving it also does
hostname resolving, which we care about. (One of those days we should
replace that by some Varlink logic between
nss-resolve/systemd-resolved.service too)
The hooks are kept in the NSS module, but they do not resolve anything
anymore, in order to keep compat at a maximum.
This changes nss-systemd to use the new varlink user/group APIs for
looking up everything.
(This also changes the factory /etc/nsswitch.conf line to use for
hooking up nss-system to use glibc's [SUCCESS=merge] feature so that we
can properly merge group membership lists).
Fixes: #12492
Lennart Poettering