Move Truecolor entries such as xterm-direct to ncurses-base

[Filipe Brandenburger]

Also reported to Debian at https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1077993

Please consider moving at least some of the Truecolor terminfo entries, such as xterm-direct, xterm-direct256, tmux-direct, etc. from the optional ncurses-term package to the ncurses-base package.

The current state of the art for Truecolor terminals is setting TERM=xterm-256color and COLORTERM=truecolor (or COLORTERM=24bit) but there are quite a few issues with this approach, such as COLORTERM not being preserved across ssh or sudo, not to mention this is a misue of the xterm-256color terminfo entry.

It would be great to be able to use TERM=xterm-direct or TERM=xterm-direct256 instead, but that requires the terminfo entry to be available mostly everywhere and unfortunately that's not the case yet. The TERM environment variable doesn't have a graceful fallback mechanism, so in order to be able to set it correctly we first really need to make sure the entries are really available everywhere.

This is an effort to try to make those entries more pervasive so that they're actually viable as $TERM settings.

To some extent we can get by with installing ncurses-term everywhere, but since the main point of that package is to include additional rare odd non-standard terminfo entries and we're hoping to make these the new default at some point (as most terminal emulators support Truecolor these days) it would be great to include it into the default.

It would be great if this could be backported to the most recent LTS version of Ubuntu, but at least getting it into new releases would ensure at some point it would get into the next LTS and as that gets deployed the entries would become as pervasive as possible.