Server entry point cleanup

#### What's this PR do?
This PR is a general pass at cleaning up the server entry point file.  The goal is better code organization as well as better practices.

Things happening here:
* `ds-mdata-server.js` is renamed to `server.js`.  This is a common pattern in the node world.  **THIS IS A BREAKING CHANGE** - the method in which this server is started will need to be updated.  You can simply change it to `npm start`

* Moves routes into a separate router file.  This cleanups the server entry point making it a little more readable and is the logically start to better MVC style code organization

#### Where should the reviewer start?
* server.js & app/router.js

#### How should this be manually tested?
* npm start - start the sever
* ensure the endpoints are still available

#### What are the relevant tickets?

Fixes #40