Feature/person, event, OU dynapi crud

Created by: ivanmrsulja

VIVO GitHub issues 3873, 3874, 3875

What does this pull request do?

Added basic CRUD procedures for Person, Organisation Unit and Event entities.

What's new?

Addition of required .n3 files containing implementation of basic CRUD operations on before mentioned entities.

How should this be tested?

You can test this using VIVI's built-in Swagger docs or use a client mocking software such as Postman or cURL.

Postman collection is avaliable here.

Interested parties

@chenejac @litvinovg @brianjlowe @milospp