feat(cli): Add D-Bus helper functions for CLI commands.

This introduces `simple_call`, a utility function to interact with D-Bus
interfaces within the RevPi system. It facilitates method invocation on
specific interfaces and paths, improving modularity and code reuse in
middleware operations.

src/revpi_middleware/cli_commands/dbus_helper.py

@@ -0,0 +1,36 @@
+# SPDX-FileCopyrightText: 2025 KUNBUS GmbH
+# SPDX-License-Identifier: GPL-2.0-or-later
+"""D-Bus helper functions for cli commands."""
+from pydbus import SystemBus
+
+from ..dbus_middleware1 import REVPI_DBUS_BASE_PATH
+from ..dbus_middleware1 import REVPI_DBUS_NAME
+
+PICONTROL_INTERFACE = "com.revolutionpi.middleware1.picontrol"
+RESET_DRIVER_METHOD = "ResetDriver"
+
+
+def simple_call(method: str, *args, interface: str, object_path=REVPI_DBUS_BASE_PATH):
+    """
+    Executes a method on a specific D-Bus object interface within the RevPi system. This function
+    connects to the system bus, retrieves the desired interface and object path, and invokes
+    the specified method with provided arguments.
+
+    Parameters:
+    method: str
+        The name of the method to be invoked on the targeted interface.
+    *args: tuple
+        Positional arguments to be passed to the method being invoked.
+    interface: str
+        The name of the D-Bus interface providing the required functionality.
+    object_path: str, optional
+        The D-Bus object path of the RevPi interface. Defaults to REVPI_DBUS_BASE_PATH.
+
+    Returns:
+    Any
+        The result of the method invocation on the targeted D-Bus interface.
+    """
+    bus = SystemBus()
+    revpi = bus.get(REVPI_DBUS_NAME, object_path)
+    iface = revpi[interface]
+    return getattr(iface, method)(*args)