refactor of model targets and constraints, addition of new constraint types and constraint construction process

app/models/targets/target.py

@@ -0,0 +1,31 @@
+from __future__ import annotations
+from typing import TYPE_CHECKING
+
+from pydantic import BaseModel
+from typing import Optional
+
+from pulp import lpSum
+
+if TYPE_CHECKING:
+    from models.solver_run import SolverRun
+    from models.problem import Problem
+
+class Target(BaseModel):
+    theta: float
+    value: float
+    result: Optional[float] = None
+    drift: float = 0.0
+
+    @classmethod
+    def max_drift(cls) -> int:
+        return 15
+
+    @classmethod
+    def max_drift_increment(cls) -> int:
+        return 1 # 10%
+
+    def minimum(self) -> float:
+        return self.value - (self.value * self.drift)
+
+    def maximum(self) -> float:
+        return self.value + (self.value * self.drift)