User module | Login Feature

### User story:
As a User, He/She can login into the website with email and password . If the user is already not registered that user won't allow before register.

### DAO:
- [ ] getEmailByUser()

### Service:
- [ ] login()

### ServiceTest:
TestLoginFeature
- [ ] testLoginSuccess
- [ ] testLoginNotSuccess
- [ ] testLoginWrongEmail
- [ ] testLoginWrongPassword

### Estimation:
- 4 Hours.

### Flow Chart
```mermaid
flowchart TB
Start((Start))
GetUserCredentials((Get User Credentials))
ValidateInput{Validate Input}
CheckDatabase((Check Database))
Authenticate{Authenticate User}
GrantAccess((Grant Access))
End((End))
Start --> GetUserCredentials
GetUserCredentials --> ValidateInput
ValidateInput --> |Valid| CheckDatabase
ValidateInput --> |Invalid| End

CheckDatabase --> Authenticate
Authenticate --> |Valid| GrantAccess
Authenticate --> |Invalid| End

```