Feature: add typescript integration

[sammyl720]

Include typescript integration

Features

1. Use ES6 module imports
2. Use enums for image size options
3. Use interfaces for route request body validation

Notes

All typescript code is contained within the src folder.

The dev script will execute and watch the typescript code for changes

npm run dev

There is a build script to transpile the code to javascript to a dist folder

npm run build

The start script expects that the typescript has already been transpiled to the dist folder

npm start