add machine subcommand

pkgs/clan-cli/clan_cli/machines/folders.py

@@ -0,0 +1,11 @@
+from pathlib import Path
+
+from ..dirs import get_clan_flake_toplevel
+
+
+def machines_folder() -> Path:
+    return get_clan_flake_toplevel() / "machines"
+
+
+def machine_folder(machine: str) -> Path:
+    return machines_folder() / machine