feat(cli): Add CLI support for RevPi configuration object (revpi-config)

This implements a new command "config" in the CLI to handle RevPi
configuration. It includes parsing and subparser setup for
configuration-related operations. The change improves usability by
extending CLI functionality to manage RevPi configuration objects.

src/revpi_middleware/cli_commands/cli_base.py

@@ -29,6 +29,11 @@ def setup_command_line_arguments():
         help="RevPi PiControl object",
     )
     cli_picontrol.add_subparsers(obj_picontrol)
+    obj_config = rpictl_obj.add_parser(
+        "config",
+        help="RevPi configuration object (revpi-config)",
+    )
+    cli_config.add_subparsers(obj_config)
 
 
 def main() -> int:
@@ -39,6 +44,9 @@ def main() -> int:
     if obj == "picontrol":
         rc = cli_picontrol.main()
 
+    elif obj == "config":
+        rc = cli_config.main()
+
     else:
         log.error(f"Unknown object: {obj}")
         rc = 1