feat: add role/permission system with tests support

- Add Role model with 17 default permissions
- Add init_wizard to create admin/guest roles on first startup
- Protect admin role from modification/deletion via API
- Fix MilestoneCreate schema (project_id optional)
- Fix delete role to clean up role_permissions first
- Add check_project_role RBAC function

app/schemas/schemas.py

@@ -211,7 +211,7 @@ class MilestoneBase(BaseModel):
 
 
 class MilestoneCreate(MilestoneBase):
-    project_id: int
+    project_id: Optional[int] = None
     pass