feat(cli): Add 'list-features' action to CLI config commands

Introduce a new 'list-features' action to display all available features
via CLI. Updated argument handling to make 'feature' optional for
'list-features' and added a validation step to ensure the feature name
is provided for other actions.

src/revpi_middleware/cli_commands/cli_config.py

@@ -4,7 +4,7 @@
 from argparse import ArgumentParser
 from logging import getLogger
 
-from .dbus_helper import BusType, simple_call
+from .dbus_helper import BusType, get_properties, simple_call
 from .. import proginit as pi
 from ..dbus_middleware1 import extend_interface
 
@@ -14,32 +14,15 @@ log = getLogger(__name__)
 def add_subparsers(parent_parser: ArgumentParser):
     parent_parser.add_argument(
         "action",
-        choices=["enable", "disable", "status", "available"],
-        help="Action to be executed: enable, disable, status or available",
+        choices=["enable", "disable", "status", "available", "list-features"],
+        help="Action to be executed: enable, disable, status or available. "
+             "To get all available features, use 'list-features'.",
     )
-
-    # Load dynamic features from dbus
-    simple_call()
-
     parent_parser.add_argument(
         "feature",
-        choices=[
-            "gui",
-            "revpi-con-can",
-            "dphys-swapfile",
-            "pimodbus-master",
-            "pimodbus-slave",
-            "systemd-timesyncd",
-            "ssh",
-            "nodered",
-            "noderedrevpinodes-server",
-            "revpipyload",
-            "bluetooth",
-            "ieee80211",
-            "avahi",
-            "external-antenna",
-        ],
-        help="Name des Features, das konfiguriert werden soll",
+        nargs="?",
+        default="",
+        help="Name of the feature to configer. To list all features use 'list-features' as action.",
     )
 
 
@@ -48,6 +31,21 @@ def main() -> int:
     dbus_value = False
     try:
 
+        if action == "list-features":
+            dbus_value = get_properties(
+                "available_features",
+                interface=extend_interface("RevpiConfig"),
+                bus_type=BusType.SESSION if pi.pargs.use_session_bus else BusType.SYSTEM,
+            )
+            for feature in dbus_value:
+                print(feature)
+
+            return 0
+
+        # For the following actions, a feature name is required
+        if pi.pargs.feature == "":
+            raise Exception("Feature name is required")
+
         if action == "enable":
             simple_call(
                 "Enable",