systemctl: whitespace optimization of --help

systemctl: whitespace optimization of --help

Move the explanation of options three columns to the right: then almost
all options fit and we do not need to break lines so often.

When a multi-line explanation precedes a section break, i.e. there is a
half-line on the right side, do not use an empty space. This saves a line,
and actually looks visually better because the text is still clearly
separated, but we don't get the big vertical white space.