mconf: line wrap columns nicely
mconf: line wrap columns nicely

I've picked 160 characters as a default because anything less than that
looks terrible and has awful wrapping going on. However, this respects
the $COLUNNS environment variable if set, and otherwise will query the
terminal to determine the size.

This is all achieved through an application of shtuil.get_terminal_size,
textwrap, print formatters, and iteration.

Fixes #6965

pexip/meson,QuLogic/meson,QuLogic/meson,jpakkane/meson,pexip/meson,jpakkane/meson,mesonbuild/meson,pexip/meson,pexip/meson,pexip/meson,mesonbuild/meson,jpakkane/meson,jpakkane/meson,QuLogic/meson,QuLogic/meson,mesonbuild/meson,jpakkane/meson,pexip/meson,mesonbuild/meson,mesonbuild/meson,jpakkane/meson,jpakkane/meson,jpakkane/meson,pexip/meson,QuLogic/meson,pexip/meson,QuLogic/meson,jpakkane/meson,mesonbuild/meson,mesonbuild/meson,QuLogic/meson,pexip/meson,QuLogic/meson,mesonbuild/meson,mesonbuild/meson,pexip/meson,mesonbuild/meson,QuLogic/meson