Catch up with changes in ncurses in base

Switch from bdb hashed database to directory tree databases
Allow to lookup for terminfo files in ${LOCALBASE}/share/site-terminfo

Meaning ports can now install their own file definition in
${LOCALBASE}/share/site-terminfo
and do not need to tun tic at all at install time.

Reviewed by: swills (maintainer)
Approved by: swills (maintainer)
Differential Revision: https://reviews.freebsd.org/D28930