doc: improve systemd-resolved integration by adding stop command
doc: improve systemd-resolved integration by adding stop command

RemainAfterExit=yes avoids the oneshot job from running stop commands
immediatly after running the start ones. ExecStopPost is used instead
of ExecStop because the later is skipped if start commands failed.

Signed-off-by: Simon Deziel <eca3f1a14b730e70ce4898287e4fc2f9966fa3a6@canonical.com>

stgraber/lxd,stgraber/lxd,lxc/lxd,lxc/lxd,lxc/lxd,hallyn/lxd,hallyn/lxd,lxc/lxd,hallyn/lxd,stgraber/lxd,lxc/lxd,lxc/lxd,hallyn/lxd,hallyn/lxd,stgraber/lxd,stgraber/lxd,stgraber/lxd,stgraber/lxd,lxc/lxd,hallyn/lxd