bsdinstall: always install FreeBSD-base.conf if using pkgbase

[ifreund_freebsdfoundation.org]

Summary

Currently bsdinstall does not install FreeBSD-base.conf when performing
an offline pkgbase installation. This commit fixes that.

PR: 287821
Sponsored by: The FreeBSD Foundation

[ifreund_freebsdfoundation.org]

Git branch: https://github.com/ifreund/freebsd-src/tree/bsdinstall-freebsd-base-conf

[grahamperrin]

Compare with the precedent of a single file:

/etc/pkg/FreeBSD.conf

– for multiple FreeBSD repos. With one of my test machines, for example,

#
# To disable a repository, instead of modifying or removing this file,
# create a /usr/local/etc/pkg/repos/FreeBSD.conf file, e.g.:
#
#   mkdir -p /usr/local/etc/pkg/repos
#   echo "FreeBSD-ports: { enabled: no }" > /usr/local/etc/pkg/repos/FreeBSD.conf
#   echo "FreeBSD-kmods: { enabled: no }" >> /usr/local/etc/pkg/repos/FreeBSD.conf
#

FreeBSD-ports: {
  url: "pkg+https://pkg.freebsd.org/${ABI}/quarterly",
  mirror_type: "srv",
  signature_type: "fingerprints",
  fingerprints: "/usr/share/keys/pkg",
  enabled: yes
}
FreeBSD-kmods: {
  url: "pkg+https://pkg.freebsd.org/${ABI}/kmods_quarterly_${VERSION_MINOR}",
  mirror_type: "srv",
  signature_type: "fingerprints",
  fingerprints: "/usr/share/keys/pkg",
  enabled: yes
}

Context

pkg.conf: Use kmod repositories · freebsd/freebsd-src@a47542f for release/14.3.0 was followed by:

• pkg.conf: add valid configurations for kmods for all branches · freebsd/freebsd-src@db6f6cc