moonraker: return list of registered directors in server.info response

Signed-off-by:  Eric Callahan <arksine.code@gmail.com>

moonraker/moonraker.py

@@ -468,11 +468,16 @@ class Server:
         return "ok"
 
     async def _handle_info_request(self, web_request):
+        file_manager = self.lookup_plugin('file_manager', None)
+        reg_dirs = []
+        if file_manager is not None:
+            reg_dirs = file_manager.get_registered_dirs()
         return {
             'klippy_connected': self.klippy_connection.is_connected(),
             'klippy_state': self.klippy_state,
             'plugins': list(self.plugins.keys()),
-            'failed_plugins': self.failed_plugins}
+            'failed_plugins': self.failed_plugins,
+            'registered_directories': reg_dirs}
 
 class KlippyConnection:
     def __init__(self, on_recd, on_close):

moonraker/plugins/file_manager.py

@@ -117,6 +117,9 @@ class FileManager:
     def get_sd_directory(self):
         return self.file_paths.get('gcodes', "")
 
+    def get_registered_dirs(self):
+        return list(self.file_paths.keys())
+
     def get_fixed_path_args(self):
         return dict(self.fixed_path_args)