New port: x11/ly: TUI (ncurses-like) display manager for X and Wayland

Ly is a lightweight TUI (ncurses-like) display manager for Linux and BSD.

It supports both X11 and Wayland sessions.

WWW: https://github.com/cylgom/ly

Reviewed by: mat
Differential Revision: https://reviews.freebsd.org/D22228