feat: Add session bus option for local testing and development

Introduced a `--use-session-bus` flag to optionally use the D-Bus
session bus instead of the system bus. This allows better flexibility
for local testing and development scenarios without requiring
system-level changes. Updated related classes and functions to respect
the new flag.

src/revpi_middleware/dbus_middleware1/bus_provider.py

@@ -6,7 +6,7 @@ from logging import getLogger
 from threading import Thread
 
 from gi.repository import GLib
-from pydbus import SystemBus
+from pydbus import SessionBus, SystemBus
 
 from . import REVPI_DBUS_NAME
 from .process_image import InterfacePiControl
@@ -20,11 +20,12 @@ class BusProvider(Thread):
         self,
         picontrol_device="/dev/piControl0",
         config_rsc="/etc/revpi/config.rsc",
+        use_system_bus=True,
     ):
         log.debug("enter BusProvider.__init__")
         super().__init__()
 
-        self._bus = SystemBus()
+        self._bus = SystemBus() if use_system_bus else SessionBus()
         self._loop = GLib.MainLoop()
 
         self.picontrol_device = picontrol_device