[new] mail/meli: a new terminal email client

Hi,

here's a wip port of https://meli.delivery, i've chosen to port the git
head instead of the last-year-old alpha-0.7.2 tag - there's wip support
for jmap (which im also poking at).

totally untested for now, but looks nice and simple. It starts and
there's a step-by-step assistant for configuration.

https://meli.delivery/documentation.html#quick-start
https://meli.delivery/documentation.html#meli.7 is the full tutorial

meli man feature broken for now, since i think it relies on gzipped
manpages, but i'll eventually have a look. plain manpages shipped in the
package works.

Landry