chore: add initial model and unit test

models/dayabay_v0.py

+from dagflow.bundles.load_variables import load_variables
+
+def model_dayabay_v0():
+	pass

tests/models/dayabay_v0.py

+from models.dayabay_v0 import model_dayabay_v0
+
+def test_dayabay_v0():
+	model = model_dayabay_v0()