pkgs/cli: Add --password flag to machines install

Add `--password` flag to `clan machines install`,
which allows installing through the `nixos-image` installer
manually without extra configuration.

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

@@ -148,6 +148,9 @@ def install_command(args: argparse.Namespace) -> None:
         target_host = str(machine.target_host)
         password = None
 
+    if args.password:
+        password = args.password
+
     if not target_host:
         msg = "No target host provided, please provide a target host."
         raise ClanError(msg)
@@ -240,6 +243,10 @@ def register_install_parser(parser: argparse.ArgumentParser) -> None:
         help="ssh address to install to in the form of user@host:2222",
     )
     add_dynamic_completer(target_host_parser, complete_target_host)
+    parser.add_argument(
+        "--password",
+        help="specify the password for the ssh connection (generated by starting the clan installer)",
+    )
     group.add_argument(
         "-P",
         "--png",