User module | Register Feature

### User story:
As a User, He/She can create account in the website to access the website's features and services.

### DAO:
- [ ] createUser()

### Service:
- [ ] registerUser()

### ServiceTest:
TestRegisterFeature
- [ ] testRegistrationSuccess
- [ ] testNullUser
- [ ] testRegistrationExistsingUser

### Estimation:
- 5 Hours.

### Flow:
```mermaid
flowchart TB
Start((Start))
CheckAvailability((Check Availability))
UsernameAvailable{email Available?}
EnterDetails((Enter Details))
ValidateInfo{Validate Information}
CreateAccount((Create Account))
StoreData((Store Data))
SendConfirmation{Send Confirmation}
Success((Success))
End((End))

Start --> CheckAvailability
CheckAvailability --> UsernameAvailable
UsernameAvailable --> |Yes| EnterDetails
UsernameAvailable --> |No| End
EnterDetails --> ValidateInfo
ValidateInfo --> |Valid| CreateAccount
ValidateInfo --> |Invalid| End
CreateAccount --> StoreData
StoreData --> SendConfirmation
SendConfirmation --> |Sent| Success
SendConfirmation --> |Not Sent| End

```