systemctl: refactor significantly

Thanks to: openfbtd (https://fleshless.org)
man: systemctl: document load, dump and clear-jobs
control-request: drop list-dependencies, use output of dump/show instead
control-request: drop is-active, parse output of dump instead
systemctl: add reset_args()
systemctl: add all other options, sans the unit ones
main: add control loop
main-no-init: whitespace
initctl: use independent Manager object for now, send control cmd later on