Add employees management module with database schema and validation

- Introduced `EmployeesModule` to manage employee data, including read and write controllers.
- Created database migrations for the `employees` table, including constraints and unique indexes.
- Implemented validation for employee fields such as name, code, and position with corresponding utility functions.
- Developed service and repository layers for handling employee data operations.
- Added unit tests for the employees service, repository, and controllers to ensure functionality and correctness.
- Updated application module to include the new `EmployeesModule` for better organization.

src/modules/configuration/configuration.module.ts

@@ -2,9 +2,10 @@ import { Module } from '@nestjs/common';
 import { BranchesModule } from './branches/branches.module';
 import { CustomersModule } from './customers/customers.module';
 import { DivisionsModule } from './divisions/divisions.module';
+import { EmployeesModule } from './employees/employees.module';
 
 @Module({
-  imports: [DivisionsModule, BranchesModule, CustomersModule],
-  exports: [DivisionsModule, BranchesModule, CustomersModule],
+  imports: [DivisionsModule, BranchesModule, CustomersModule, EmployeesModule],
+  exports: [DivisionsModule, BranchesModule, CustomersModule, EmployeesModule],
 })
 export class ConfigurationModule {}