Auto-detect device

[Eeems]

Instead of requiring the user to pass the --rm1 flag, it would be preferable to auto-detect the device where possible.

[Eeems]

codexctl/codexctl/__init__.py

Lines 239 to 244 in d800640

	def is_rm():
	if not os.path.exists("/sys/devices/soc0/machine"):
	return False
	with open("/sys/devices/soc0/machine") as f:
	return f.read().strip().startswith("reMarkable")

This is most of the way to detecting which device. /sys/devices/soc0/machine will contain reMarkable 2.0 on a rM2, and either reMarkable 1.0 or reMarkable Prototype 1, depending on how old the OS version is.