Revamp trending projects query
This changes the query to use a COUNT nested in an INNER JOIN, instead of a COUNT plus a GROUP BY. There are two reasons for this: 1. Using a COUNT in an INNER JOIN can be quite a bit faster. 2. The use of a GROUP BY means that method calls such as "any?" (and everything else that calls "count") operate on a Hash that counts the amount of notes on a per project basis, instead of just counting the total amount of projects. The query has been moved into Project.trending as its logic is simple enough. As a result of this testing the TrendingProjectsFinder class simply involves testing if the right methods are called, removing the need for setting up database records.