refactor(ml): modularization and styling (#2835)

* basic refactor and styling

* removed batching

* module entrypoint

* removed unused imports

* model superclass,  model cache now in app state

* fixed cache dir and enforced abstract method

---------

Co-authored-by: Alex Tran <alex.tran1502@gmail.com>

machine-learning/app/schemas.py

@@ -1,3 +1,5 @@
+from enum import Enum
+
 from pydantic import BaseModel
 
 
@@ -54,3 +56,11 @@ class Face(BaseModel):
 
 class FaceResponse(BaseModel):
     __root__: list[Face]
+
+
+class ModelType(Enum):
+    IMAGE_CLASSIFICATION = "image-classification"
+    CLIP = "clip"
+    CLIP_VISION = "clip-vision"
+    CLIP_TEXT = "clip-text"
+    FACIAL_RECOGNITION = "facial-recognition"