models.py -> loaders/ module refactor (#2680)

* models.py -> loaders/ module refactor

* refactor ModelLoader class

* plugin manager changes

* circular import fix

* pytest

* pytest

* minor improvements

* fix

* minor changes

* fix test

* remove dead code

* coderabbit comments

* lint

* fix

* coderabbit suggestion I liked

* more coderabbit

* review comments, yak shaving

* lint

* updating in light of SP ctx manager changes

* review comment

* review comment 2

tests/e2e/test_load_model.py

@@ -6,8 +6,8 @@ import tempfile
 import pytest
 import torch
 
+from axolotl.loaders import ModelLoader, load_tokenizer
 from axolotl.utils.dict import DictDefault
-from axolotl.utils.models import ModelLoader, load_model, load_tokenizer
 
 
 @pytest.fixture(name="temp_dir")
@@ -58,6 +58,8 @@ class TestLoadModelUtils:
             ModelLoader(
                 cfg=self.cfg,
                 tokenizer="",
+                inference=False,
+                reference_model=True,
             )
         )
 
@@ -71,13 +73,8 @@ class TestLoadModelUtils:
     ):
         self.cfg.output_dir = temp_dir
         self.model_loader.tokenizer = load_tokenizer(self.cfg)  # pylint: disable=all
-        self.model_loader.model, _ = load_model(
-            self.cfg,
-            self.model_loader.tokenizer,
-            inference=False,
-            reference_model=True,
-        )
-        self.model_loader.convert_embedding_modules_dtype(
+        self.model_loader.load()
+        self.model_loader._convert_embedding_modules_dtype(
             embedding_modules, dist_dtype, before_kbit_train_or_finetune
         )
         for name, module in self.model_loader.model.named_modules():