caroot: drop VERSION tags from certs

With this change, we'll drop the "with $FreeBSD$" lines from trusted/
certs in the next update. untrusted/ will need to be done manually, but
I'll likely just do them all manually, commit, then run the script and
commit any legitimate updates after confirming the output matches what
I did manually.

Reported by: imp
Reviewed by: imp
Differential Revision: https://reviews.freebsd.org/D41597

caroot: update CA bundle processor

Our current processor was identified as trusting cert not explicitly
marked for SERVER_AUTH, as well as certs that were tagged with
DISTRUST_AFTER.

Update the script to handle both scenarios. This patch was originally
authored by mandree@ for ports, and it was subsequently ported to base
caroot.

MFC after: 3 days

caroot: add @generated tags to extracted .pem

As is the current trend; while these files are manually curated, they are
still generated. If they end up in a review, it would be helpful to also
take the hint and hide them.

[1/3] Initial infrastructure for SSL root bundle in base

This setup will add the trusted certificates from the Mozilla NSS bundle
to base.

This commit includes:
- CAROOT option to opt out of installation of certs
- mtree amendments for final destinations
- infrastructure to fetch/update certs, along with instructions

A follow-up commit will add a certctl(8) utility to give the user control
over trust specifics. Another follow-up commit will actually commit the
initial result of updatecerts.

This work was done primarily by allanjude@, with minor contributions by
myself.

No objection from: secteam
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D16856