Employee Module | Get All Employee

- [x] Employee Model
- [x] Employee Dao - get all employee
- [x] Employee Service - get all employee

## Issue Title: Implement "Get All Employees" Functionality in Employee Module

### Issue Description

We need to implement the "Get All Employees" functionality within the Employee Module. This involves defining the Employee Model, creating a method in the Employee DAO to retrieve all employees, and implementing the necessary service method in the Employee Service.

### Task Breakdown

1. **Employee Model:**
- If not already done, create an Employee Model class to represent employee data.
- Define the attributes and properties needed to store employee information, such as name, employee ID, contact details, etc.

2. **Employee DAO:**
- Implement a method named "getAllEmployees" in the Employee DAO class.
- This method should retrieve all employee records from the database or data store.
- Ensure that it returns a collection of Employee objects.

3. **Employee Service:**
- Create a "getAllEmployees" service method in the Employee Service class.
- This method should serve as an intermediary between the DAO and higher-level components.
- Call the "getAllEmployees" method from the Employee DAO to fetch all employees.
- Process and transform the data if necessary before returning it to the calling component.

### Additional Information

Please keep the following guidelines in mind while working on this issue:
- Adhere to the coding standards and conventions followed in the project.
- Implement unit tests to verify the functionality of the "Get All Employees" feature.
- Document any changes made to the codebase.
- Use meaningful commit messages that reference this issue for better traceability.