accessibility/wl-gammarelay-rs: add new port

wl-gammarelay-rs is a simple program that provides DBus interface to
control display temperature and brightness under Wayland without
flickering. Like wl-gammarelay, but written in Rust, runs on a single
thread, has three times less SLOC and uses DBus (for simplicity).

https://github.com/MaxVerevkin/wl-gammarelay-rs
(cherry picked from commit fad4602eccf7389ae56b1274c2031eda2fb936b4)