feat(dbus): Add support for configuring the external antenna

Introduce the `configure_external_antenna` function to manage external
antenna settings, including enable, disable, and status checks. Update
the feature configuration in `interface_config` to include this
functionality. This enhances WiFi-related configuration options.

src/revpi_middleware/dbus_middleware1/system_config/interface_config.py

@@ -9,6 +9,7 @@ from .revpi_config import (
     ConfigActions,
     configure_avahi_daemon,
     configure_dphys_swapfile,
+    configure_external_antenna,
     configure_gui,
     simple_systemd,
 )
@@ -92,5 +93,5 @@ AVAILABLE_FEATURES = {
     "bluetooth": False,
     "ieee80211": False,
     "avahi": FeatureFunction(configure_avahi_daemon, []),
-    "external-antenna": False,
+    "external-antenna": FeatureFunction(configure_external_antenna, []),
 }

src/revpi_middleware/dbus_middleware1/system_config/revpi_config.py

@@ -213,6 +213,31 @@ def configure_dphys_swapfile(action: ConfigActions):
     return return_value
 
 
+def configure_external_antenna(action: ConfigActions):
+    revpi = RevPiConfig()
+    if action is ConfigActions.AVAILABLE:
+        return revpi.with_wifi
+
+    config_txt = ConfigTxt()
+
+    if action is ConfigActions.ENABLE and revpi.with_wifi:
+        config_txt.clear_dtparams(["ant1", "ant2"])
+        config_txt.add_name_value("dtparam", "ant2")
+        config_txt.save_config()
+
+    elif action is ConfigActions.DISABLE and revpi.with_wifi:
+        config_txt.clear_dtparams(["ant1", "ant2"])
+        config_txt.save_config()
+
+    elif action is ConfigActions.STATUS:
+        return revpi.with_wifi and "ant2" in config_txt.get_values("dtparam")
+
+    else:
+        raise ValueError(f"action {action} not supported")
+
+    return None
+
+
 def configure_gui(action: ConfigActions):
     gui_available = access("/usr/bin/startx", X_OK)