This implements an "event device" listener plugin,
that enables the user to configure the phoniebox to
respond to events from an "event device" (device under /dev/input).
This incluces eg button presses from an USB controller or keyboard.

Includes a detailed how-to as well as example config

This is an actual usecase in case someone wants to setup a device
and figure out the button ids by looking at the logs

- Remove duplicated section as suggested
- Add Zero Delay Arcade USB Encoder usecase

The documentation is now part of the markdown documentation

There was some left over indentation from the old rtf format in the python code examples.

This is tighly modeled after gpio.
In contrast to GPIO, this is a list of devices containing
each one or more input/output devices.
Eg a Joystick has keys but potentially also rumble or leds.

Currently only very simply input devices (buttons) are supported.
This structer should enable to extend this easily.

As suggested this should be a separate file, similar to the gpioz config

Now the config for evdev is akin to GPIO.
The big difference is that multiple devices with each
multiple input/output devices are supported.

Note that the backend is still the old event device listener backend.
Thus to support more features, the backend would need to be
quite drastically overhauled.

The attribute 'device_request' of EvDevKeyListener is now called 'device_name_request'

Fails if there is no device_name and setts proper default for 'exact'

This is required for some tests.

Following the instructions from issue MiczFlor#2050
Specifically: MiczFlor#2050 (comment)

This reverts commit 75161b5.

As this was not working

Currently it is hard to install zmq (MiczFlor#2050) and for
CI pytest `zmq` is not available.
As the test do not really require `jukebox.publishing`
running, mocking it in the test avoids it being imported.

Thus the tests do not require `zmq` to be installed.