Create new bill

### Feature 1: Bill Creation
#### User Story:
User can create new Bill.
#### Prerequisites:
- [ ] Create Bill table
- [ ] Implement Bill model
- [ ] Implement Bill DAO (create)
- [ ] Complete Product Module Feature 1.
- [ ] Complete User Module Feature 1.
- [ ] Complete Bill Details Module Feature 1.

#### Validations:

##### Form Validation:

- [ ] User Id ( id<1 )
- [ ] Time Stamp
- [ ] Bill DTO ( null )

##### Business Validation:

- [ ] Check The Bill Table Exist or not.
#### Messages:
- Invalid User ID.
- User doesn't exists.
- Invalid Bill Details.
- Bill Table Not Found

#### Flow:

```mermaid
graph TD;

A[Bill Service: Create Bill] --> B[Form Validation]
B -- Yes --> C{Business Validation}
B -- No --> F[Throws Exception]
C -- Yes --> D[Bill DAO : Create Bill]
C -- No --> G[Bill Service : Bill Table Not Found]
D --> E[Bill Service: Bill Created ]

```