Add OpenAPI support

[lukasturcani]

This PR adds boilerpate allowing the creation of Swagger documentation via the swagger-ui-express dependency.

The first endpoint im adding is /api/v2/auto-experiments which allows the querying and filtering of auto-experiments

How it works

• nomad-rest-api/app.js: Has a new object called swaggerDocument this object documents the api and is used to generate the Swagger docs. For each path, an object which defines the api of that path is added. I'm defining these objects in controlers/v2/auto-experiments.js so that the documentation object is next to the function it is documenting.
• new endpoint /api-docs where you can view the swagger documentation -- see image below
• nomad-rest-api/contorllers/auth.js - ive added a documentation boject for the auth endpoint so that it appears in the swagger docs
• nomad-rest-api/contorllers/v2/auto-experiments.js- ive added enpoints for/api/v2/auto-expeirmentsand/api/v2/auto-experiments/download`
• Ive added tests for the new endpoints