Add Role Assignment Feature for Customers

- Introduced a new role assignment feature for customers, allowing roles to be assigned as either 'admin' or 'analyst'.
- Updated the Customer entity to include a Role field, enhancing the data model to support role management.
- Created new request and response forms for role assignment, ensuring proper validation and structured responses.
- Implemented the AssignRole method in the customer service layer, handling role assignment logic and error management.
- Added a new AssignRole handler to process role assignment requests via the API, complete with Swagger documentation for clarity.
- Updated routes to include the new role assignment endpoint, improving the administrative capabilities of the system.
- Enhanced logging for role assignment operations to ensure traceability and debugging ease.

cmd/web/router/routes.go

@@ -80,6 +80,7 @@ func RegisterAdminRoutes(e *echo.Echo, userHandler *user.Handler, companyHandler
 		customersGP.PUT("/:id", customerHandler.UpdateCustomer)
 		customersGP.DELETE("/:id", customerHandler.DeleteCustomer)
 		customersGP.PUT("/:id/status", customerHandler.UpdateStatus)
+		customersGP.PATCH("/:id/role", customerHandler.AssignRole)
 	}
 
 	// Admin Tenders Routes