Add Site Documenation for Mobile App Distribution

[ylberprapashtica-sl]

📃 Documentation Issue

Have you read the Contributing Guidelines on issues?

• Yes

Description

Missing Site (Account) documentation for Mobile App Distribution
Doc URL: TestFairy REST Api Documentation

Suggested Fix

Add the documentation that are related to Sites(Accounts):
List Sites,
Create New Site,
Delete Site

Documentation Checklist

• Typos
• Grammar
• Incorrect information
• Missing information