Support Load Cells as a probe option

[pellcorp]

Based on some excellent work originally from https://github.com/cryoz/K1_tenso_manual/blob/main/README_ENG.md

And now based on some excellent work from a simple af fork a lot of the work has been done for us, but we would still need to get a version of klipper with the right bed mcu firmware and any missing load cells commits

https://github.com/Sekilsgs2/creality_pellcorp

Need to figure out what parts of https://github.com/garethky/klipper/tree/load-cell-probe-community-testing are still missing from mainline klipper.