systemctl: move "dump" command from systemctl to systemd-analyze

systemctl: move "dump" command from systemctl to systemd-analyze

It's an analysis command and its format is explicitly not covered by any
stability guarantees, hence move away from systemctl and into
systemd-analyze, minimizing the already large interface of systemctl a
bit.

This patch also adds auto-paging to the various systemd-analyze commands
where that makes sense