nanobsd: Refactor cust_pkgng

[senguptaangshuman17_gmail.com]

Summary

Move the existing function to the legacy plan, as it is
incompatible with this implementation.

Create a new cust_pkgng()

[senguptaangshuman17_gmail.com]

Rebase stack on top of D59043 update

[jlduran]

tools/tools/nanobsd/customizations.sh

149–150

This removal seems unrelated.

[jlduran]

tools/tools/nanobsd/legacy.sh

631

We may reference D58888 here (https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=296409), but that part will get fixed soon. The real reason we skip with -U is because of the invalid metalog pkg may produce.

[senguptaangshuman17_gmail.com]

tools/tools/nanobsd/legacy.sh

631

should it be as part of the comment or the print message?

[jlduran]

tools/tools/nanobsd/legacy.sh

631

Comment.

[senguptaangshuman17_gmail.com]

Refactor cust_pkgng to direct tgt_pkg install and add unprivileged build check