consider palera1n for apple flashing

previously, checkra1n was being used for flashing apple devices, but as they seem to have gone silent as far as i can tell, and as checkra1n also doesn't support ios15, palera1n could be a better base to work with, as it's already open source, and supports ios 15 https://github.com/palera1n/palera1n

related : !2098 (closed)