sysutils/keyd: add new port

keyd has several unique features many of which are traditionally only
found in custom keyboard firmware like QMK. Some of the more
interesting ones include:

- Layers.
- Key overloading (different behaviour on tap/hold).
- Per keyboard configuration.
- Instantaneous remapping (no flashing required).
- A simple and intuitive config format.
- Being display server agnostic (works on wayland and virtual console alike).

https://github.com/rvaiya/keyd