[le12] rpi-tools: backport of PR9592 - add gpiod support

[HungerHa]

EDIT: This is the backport of #9592 for LibreELEC 12

gpiod are the official Python bindings for libgpiod. libgpiod is already part of the system tools add-on, only these Python bindings are currently missing to be able to use it in Python scripts.

lgpio and gpiozero are easier to use, but currently have some insurmountable problems, as I have tried to explain here:

Feature request: RPi-Tools with official Python bindings for libgpiod

[chewitt]

NB: This should be submitted to master branch first, and then submitted as a backport to libreelec-12.0 branch; either in parallel or after successful merge to master.

[HungerHa]

NB: This should be submitted to master branch first, and then submitted as a backport to libreelec-12.0 branch; either in parallel or after successful merge to master.

I will prepare a second PR for the master branch and would leave this one open for a subsequent backport to LE12.

[chewitt]

I will prepare a second PR for the master branch and would leave this one open for a subsequent backport to LE12.

Please squash the commits here. Thanks.

[HungerHa]

Please squash the commits here. Thanks.

You are welcome. Because I used it too infrequently before, it felt like open heart surgery, but now it's squashed.