This commit includes the following changes:

1. Addition of `checkEmpIdExists` middleware to check if an employee ID already exists in the database.
2. Addition of `checkEmpIdActivityExists` middleware to check if an employee has any activity associated with the given employee ID.
3. Implementation of `/addEmployee` API endpoint to add new employee details.
4. Implementation of `/updateEmployee` API endpoint to update existing employee details.
5. Implementation of `/getmaster-data` API endpoint to fetch employee roles and statuses.
6. Implementation of `/deleteActivity` API endpoint to delete an employee's activity.
7. Implementation of `/addMasterActivity` API endpoint to add a new master activity.
8. Implementation of `/deleteMasterActivity` API endpoint to delete a master activity.

These changes are focused on managing employee data and master activity data in the application.