MFC r255035:

Add a few missing language directories for /usr.
MFC r248979 (emaste):

Format per etc/mtree/README

- Spaces instead of tabs
- Sort some i18n entries
MFC r255036:

Add directories that is installed as part of bsdconfig.

These are included unconditionally for now because bsdconfig
is currently installed unconditionally.

This fixes 'make -j 17 installworld' caused by a race
condition.