Create Feed Service

## Description
This sets up a service to get the feed on a specific note. It takes in one url parameter (lastRequest) that if null pulls all snippets from the last 5 minutes otherwise it will grab everything since that last request. The snippets are then sorted by their creation datetime and sent as an array of objects to the front-end.

 I did test with temporary ajax requests just to make sure it works as expected since we don't have an interface that uses this service yet.