Event Registration

### Description
As a user, I am able to register for the event. When I click the register button, I am able to fill in the form input. The form input has 2 inputs, fullname and email. After that, the expectation of the result is I will be registered for the event

### Goal
Able to register for the event

### Tasks

- [x] Slicing modal event register
- [x] Create API for event registration 
