Automatically configure GrumpyScreen on RPI

[pellcorp]

So for a DSI screen or HDMI screen ideally, we would try and automatically do some basic config, even if its just the LVGL_EVDEV_DEV in the /etc/systemd/system/grumpyscreen.service which should be something other than /dev/input/by-path/platform-soc:firmware:touchscreen-event for HDMI, so something like: /dev/input/by-id/usb-BIQU_BTT-HDMI5_SN0000000003-event-if00

[pellcorp]

For some reason DSI does not provide a by-id link for input

[pellcorp]

This requires us also making changes to the /boot/firmware/config.txt too, so im actually not entirely sure its a good idea to automatically install it.