BREAKING CHANGES: invocations now require model key, not base/type/name

- Implement new model loader and modify invocations and embeddings

- Finish implementation loaders for all models currently supported by
  InvokeAI.

- Move lora, textual_inversion, and model patching support into
  backend/embeddings.

- Restore support for model cache statistics collection (a little ugly,
  needs work).

- Fixed up invocations that load and patch models.

- Move seamless and silencewarnings utils into better location

tests/test_model_probe.py

@@ -2,7 +2,7 @@ from pathlib import Path
 
 import pytest
 
-from invokeai.backend import BaseModelType
+from invokeai.backend.model_manager import BaseModelType, ModelRepoVariant
 from invokeai.backend.model_manager.probe import VaeFolderProbe
 
 
@@ -21,10 +21,10 @@ def test_get_base_type(vae_path: str, expected_type: BaseModelType, datadir: Pat
     base_type = probe.get_base_type()
     assert base_type == expected_type
     repo_variant = probe.get_repo_variant()
-    assert repo_variant == "default"
+    assert repo_variant == ModelRepoVariant.DEFAULT
 
 
 def test_repo_variant(datadir: Path):
     probe = VaeFolderProbe(datadir / "vae" / "taesdxl-fp16")
     repo_variant = probe.get_repo_variant()
-    assert repo_variant == "fp16"
+    assert repo_variant == ModelRepoVariant.FP16