TrainerConfig inherit from InstantiateConfig (#1175)

Making TrainerConfig an InstantiateConfig so it can be swapped in and out with different methods. Also made the TrainerConfig a subclass of ExperimentConfig (which was changed from a printableconfig to an instantiateconfig), since we were already instantiating the Trainer class with the ExperimentConfig

Removed the "config" field from the TrainerCallbackAttributes struct to eliminate circular dependencies when types are checked.

Minor scripts and docs changes to accommodate the update to the config struct, meaning the flags that were associated with the TrainerConfig were moved up to the top level of the config.

tests/test_train.py

@@ -9,19 +9,19 @@ from pathlib import Path
 
 import pytest
 
-from nerfstudio.configs.experiment_config import ExperimentConfig
 from nerfstudio.configs.method_configs import method_configs
 from nerfstudio.data.dataparsers.blender_dataparser import BlenderDataParserConfig
 from nerfstudio.data.dataparsers.minimal_dataparser import MinimalDataParserConfig
+from nerfstudio.engine.trainer import TrainerConfig
 from scripts.train import train_loop
 
 BLACKLIST = ["base", "semantic-nerfw", "instant-ngp", "instant-ngp-bounded", "nerfacto", "phototourism"]
 
 
-def set_reduced_config(config: ExperimentConfig):
+def set_reduced_config(config: TrainerConfig):
     """Reducing the config settings to speedup test"""
     config.machine.num_gpus = 0
-    config.trainer.max_num_iterations = 2
+    config.max_num_iterations = 2
     # reduce dataset factors; set dataset to test
     config.pipeline.datamanager.dataparser = BlenderDataParserConfig(data=Path("tests/data/lego_test"))
     config.pipeline.datamanager.train_num_images_to_sample_from = 1