User module | Register Feature

# User Story

As a user, I should be able to register in the application using a valid first name, last name, username, and email. If the first name is invalid, the error message will be "User first name is not valid." If the last name is invalid, the error message will be "User last name is not valid." If the username is invalid, the error message will be "User username is not valid." If the email is invalid, the error message will be "User email is not valid." If the password is invalid, the error message will be "User password is not valid."

### DAO:

- [x] createUser()
- [x] getAllUser()
- [x] findUserByEmail()
- [x] updateUser()
- [x] deleteUser()

### Service:
- [x] registerUser()

### Service Tests:
- [x] testRegisterUser()

### Flow

```mermaid
flowchart TD
A[Start]
B[Display Registration Form]
C[User Fills out Form]
D[Validate Information]
E{Validation Successful?}
F[Save User Data]
G[Registration Successful]
H[Display Error Messages]
I[End]
A --> B
B --> C
C --> D
D --> E
E -- Yes --> F
F --> G
E -- No --> H
H --> B
H --> I
G --> I
```