feat: implement user and role models with password hashing, and add tests for user functionality

models/__init__.py

@@ -14,6 +14,7 @@ from .metadata import (
 from .project import MiningOperationType, Project
 from .scenario import Scenario, ScenarioStatus
 from .simulation_parameter import DistributionType, SimulationParameter
+from .user import Role, User, UserRole, password_context
 
 __all__ = [
     "FinancialCategory",
@@ -32,4 +33,8 @@ __all__ = [
     "STOCHASTIC_VARIABLE_METADATA",
     "ResourceDescriptor",
     "StochasticVariableDescriptor",
+    "User",
+    "Role",
+    "UserRole",
+    "password_context",
 ]