Final ui and api endpoint changes

[codinger41]

What does this PR do?

It has all Essential files and directories needed to run the EventsManager App

Description of Task to be completed?

The UI template which is in the template directory has been completed with HTML, CSS and JS.
The Server directory has the API routes, controllers and models directory that should power up the API.
The Controller directory has 2 files- eventController and centerController. Both files are the main files powering up the API Routes.
The Models directory has dummy data for Events and Centers as welll.
The Routes directory is responsible to API routing and versioning.

How should this be manually tested?

run Npm install to install all dependencies,
run Npm start to start the express server.

To test the API, open up an API tester like POSTMAN and test these routes:
GET http://localhost/events
GET http://localhost/events/eventId
POST http://localhost/events
PUT http://localhost/events/eventId
DELETE http://localhost/events/eventId

POST http://localhost/centers
GET http://localhost/centers
GET http://localhost/centers/centerId
PUT http://localhost/centers/centerId
DELETE http://localhost/centers/centerId

Any background context you want to provide?

What are the relevant pivotal tracker stories? (if applicable)

1.Users should be able to create events, delete events and modify events.
2.Admin should be able to add centers, delete centers and Edit centers