certctl: Set METALOG ownership to root:wheel

This sets the correct ownership values when building base.txz

This is an updated version of commit 10fa3f2518d4, omitting the
-N ${DESTDIR}${DISTBASE}/etc from the original commit.

install(1) does not validate the arguments passed to -o or -g
(see PR283355) so there's no need to have the passwd db available
for now. Future work includes plumbing the appropriate passwd db
path through certctl, and validating uid and gid in install(1).

PR: 283340
Reviewed by: jrtc27
Differential Revision: https://reviews.freebsd.org/D48506