Remove disk_config from user configuration

Author: cbrookins

arch/user_configuration.json

@@ -11,7 +11,6 @@
     "auth_config": {},
     "bootloader": "Systemd-boot",
     "custom_commands": [],
-    "disk_config": none,
     "hostname": "archlinux",
     "kernels": [
         "linux-lts"