Use pyyaml to generate valid configuration output

The custom yaml generator made an invalid yaml file that needed to be
fixed, by using the already included pyyaml library we can make sure the
output is valid.

meshtastic/__main__.py

@@ -20,6 +20,8 @@ from meshtastic import portnums_pb2, channel_pb2, config_pb2
 from meshtastic.globals import Globals
 from meshtastic.__init__ import BROADCAST_ADDR
 
+from google.protobuf.json_format import MessageToDict
+
 def onReceive(packet, interface):
     """Callback invoked when a packet arrives"""
     our_globals = Globals.getInstance()
@@ -598,6 +600,8 @@ def subscribe():
 
 def export_config(interface):
     """used in--export-config"""
+    configObj = {}
+
     owner = interface.getLongName()
     owner_short = interface.getShortName()
     channel_url = interface.localNode.getURL()
@@ -611,38 +615,34 @@ def export_config(interface):
         lon = pos.get('longitude')
         alt = pos.get('altitude')
 
-    config = "# start of Meshtastic configure yaml\n"
     if owner:
-        config += f"owner: {owner}\n\n"
+        configObj["owner"] = owner
     if owner_short:
-        config += f"owner_short: {owner_short}\n\n"
+        configObj["owner_short"] = owner_short
     if channel_url:
         if Globals.getInstance().get_camel_case():
-            config += f"channelUrl: {channel_url}\n\n"
+            configObj["channelUrl"] = channel_url
         else:
-            config += f"channel_url: {channel_url}\n\n"
+            configObj["channel_url"] = channel_url
     if lat or lon or alt:
-        config += "location:\n"
-        if lat:
-            config += f"  lat: {lat}\n"
-        if lon:
-            config += f"  lon: {lon}\n"
-        if alt:
-            config += f"  alt: {alt}\n"
-        config += "\n"
-    preferences = f'{interface.localNode.localConfig}'
-    prefs = preferences.splitlines()
-    if prefs:
-        if Globals.getInstance().get_camel_case():
-            config += "userPrefs:\n"
-        else:
-            config += "user_prefs:\n"
-        for pref in prefs:
+        configObj["location"] = { "lat": lat, "lon": lon, "alt": alt }
+    preferences = MessageToDict(interface.localNode.localConfig)
+    if preferences:
+        # Convert inner keys to correct snake/camelCase
+        prefs = {}
+        for pref in preferences:
             if Globals.getInstance().get_camel_case():
-                # Note: This may not work if the value has '_'
-                config += f"  {meshtastic.util.snake_to_camel(meshtastic.util.quoteBooleans(pref))}\n"
+                prefs[meshtastic.util.snake_to_camel(pref)] = preferences[pref]
             else:
-                config += f"  {meshtastic.util.quoteBooleans(pref)}\n"
+                # TODO: Possibly convert camel to snake?
+                prefs[pref] = preferences[pref]
+        if Globals.getInstance().get_camel_case():
+            configObj["userPrefs"] = preferences
+        else:
+            configObj["user_prefs"] = preferences
+
+    config = "# start of Meshtastic configure yaml\n"
+    config += yaml.dump(configObj)
     print(config)
     return config