Add subreddit querying to SubredditService

[kgellci]

To the SubredditService module, add a method which takes a query string for the search term and returns a list of subreddits which match the query.

You can do this by adding a new route to SubredditService/Sources/APIRoute+Subreddit.swift
The route is subreddits/search

You will then need to create a new api call in SubredditService module which uses CoreAPI.results... with the newly specified route. You will also need to pass through the query string as a parameter all the way through to CoreAPI which makes the call.

Hey I was looking at the code and while I'm unable to help with this I just wanted to say that if you can switch over the subreddit systems over to using the Reddit API's like this implies it would make something I'm trying to work on with this a lot easier so I'd also love to see this change made.