allsky_dewheater.py for the RPi5 with gpiod instead of GPIO

[Adler6907]

I modified allsky_dewheater.py slightly so that the heating relay can be switched via a GPIO again.

I replaced import RPi.GPIO as GPIO with import gpiod. gpiod is already preinstalled with bookworm.
Changes were made in allsky_dewheater.py in the functions turnHeaterOff, turnHeaterOn and dewheater. The setmode function was no longer necessary.
In allsky_shared.py the function getGPIOPin is no longer necessary for allsky_dewheater.py.
In the attachment allsky_dewheater.py which only needs to be replaced in /opt/allsky/modules [allsky_dewheater.py.txt](https://github.com/AllskyTeam/allsky-modules/files/13694157/allsky_dewheater.py.txt)

[Alex-developer]

Thanks for that,

Have a look at the dev branch as this has all of the fixes in it for Bookworm and the pi 5, we are aiming to release this in the next week