Add configurable data_dir for LMDB state storage

Author: incrypto32

src/amp/loaders/base.py

@@ -68,6 +68,7 @@ def __init__(self, config: Dict[str, Any], label_manager=None) -> None:
         state_config_dict = config.get('state', {})
         self.state_enabled = state_config_dict.get('enabled', True)
         self.state_storage = state_config_dict.get('storage', 'memory')
+        self.state_data_dir = state_config_dict.get('data_dir', '.amp_state')
         self.store_batch_id = state_config_dict.get('store_batch_id', True)
         self.store_full_metadata = state_config_dict.get('store_full_metadata', False)