BSD.root.dist: Add package tag for all directories

This fixes some missing directories, notably /boot/modules. Other
directories are not missing because they contain other files, but
they should still have their own METALOG entries and be placed in
the correct package.

MFC after: 3 days
Reported by: bdrewery
Reviewed by: cperciva, imp
Sponsored by: https://www.patreon.com/bsdivy
Differential Revision: https://reviews.freebsd.org/D52958