[core/models] Support additional command line parameters from metadata

This should fix things like the fake Fortnite "games" (Lego Fortnite etc.)

Author: derrod

legendary/core.py

@@ -733,6 +733,13 @@ def get_launch_parameters(self, app_name: str, offline: bool = False,
                 self.log.warning(f'Parsing predefined launch parameters failed with: {e!r}, '
                                  f'input: {install.launch_parameters}')
 
+        if meta_args := game.additional_command_line:
+            try:
+                params.game_parameters.extend(shlex.split(meta_args.strip(), posix=False))
+            except ValueError as e:
+                self.log.warning(f'Parsing metadata launch parameters failed with: {e!r}, '
+                                 f'input: {install.launch_parameters}')
+
         game_token = ''
         if not offline:
             self.log.info('Getting authentication token...')

legendary/models/game.py

@@ -91,6 +91,12 @@ def supports_cloud_saves(self):
     def supports_mac_cloud_saves(self):
         return self.metadata and (self.metadata.get('customAttributes', {}).get('CloudSaveFolder_MAC') is not None)
 
+    @property
+    def additional_command_line(self):
+        if not self.metadata:
+            return None
+        return self.metadata.get('customAttributes', {}).get('AdditionalCommandLine', {}).get('value', None)
+
     @property
     def catalog_item_id(self):
         if not self.metadata: