moved models to separate folder

app/models/objective_function.py

@@ -0,0 +1,12 @@
+from pydantic import BaseModel
+from typing import Dict
+
+from models.targets import Targets
+
+class ObjectiveFunction(BaseModel):
+  # minimizing tif/tcc target value is only option currently
+  # as we add more we can build this out to be more dynamic
+  # likely with models representing each objective function type
+  tif_targets: Targets
+  tcc_targets: Targets
+  weight: Dict = {'tif': 1, 'tcc': 1}