feat(dbus): Add support for configuring 'revpi-con-can' feature

Introduce the `configure_con_can` function to manage enabling,
disabling, status checking, and availability of the 'revpi-con-can'
feature. Update the `AVAILABLE_FEATURES` dictionary to integrate
'revpi-con-can' as a configurable feature.

src/revpi_middleware/dbus_middleware1/system_config/interface_config.py

@@ -8,6 +8,7 @@ from logging import getLogger
 from .revpi_config import (
     ConfigActions,
     configure_avahi_daemon,
+    configure_con_can,
     configure_dphys_swapfile,
     configure_external_antenna,
     configure_gui,
@@ -79,7 +80,7 @@ def get_feature(feature: str) -> FeatureFunction:
 
 AVAILABLE_FEATURES = {
     "gui": FeatureFunction(configure_gui, []),
-    "revpi-con-can": False,
+    "revpi-con-can": FeatureFunction(configure_con_can, []),
     "dphys-swapfile": FeatureFunction(configure_dphys_swapfile, []),
     "pimodbus-master": FeatureFunction(simple_systemd, ["pimodbus-master.service"]),
     "pimodbus-slave": FeatureFunction(simple_systemd, ["pimodbus-slave.service"]),

src/revpi_middleware/dbus_middleware1/system_config/revpi_config.py

@@ -260,6 +260,34 @@ def configure_gui(action: ConfigActions):
         raise ValueError(f"action {action} not supported")
 
 
+def configure_con_can(action: ConfigActions):
+    revpi = RevPiConfig()
+    if action is ConfigActions.AVAILABLE:
+        return revpi.with_con_bridge
+
+    dt_overlay = "revpi-con-can"
+    config_txt = ConfigTxt()
+
+    if action is ConfigActions.ENABLE and revpi.with_con_bridge:
+        config_txt.clear_dtoverlays([dt_overlay])
+        config_txt.add_name_value("dtoverlay", dt_overlay)
+        config_txt.save_config()
+        subprocess.call(["/usr/bin/dtoverlay", dt_overlay])
+
+    elif action is ConfigActions.DISABLE and revpi.with_con_bridge:
+        config_txt.clear_dtoverlays([dt_overlay])
+        config_txt.save_config()
+        subprocess.call(["/usr/bin/dtoverlay", "-r", dt_overlay])
+
+    elif action is ConfigActions.STATUS:
+        return revpi.with_con_bridge and dt_overlay in config_txt.get_values("dtparam")
+
+    else:
+        raise ValueError(f"action {action} not supported")
+
+    return None
+
+
 def simple_systemd(action: ConfigActions, unit: str):
     bus = SystemBus()
     systemd_manager = bus.get(".systemd1")