Improve cookbook search

:fork_and_knife: To provide better search results based on name this weights cookbook name over cookbook description. Since there are also a lot of cookbooks with similar names (redis, redisio, redis-test etc.) this also takes into account follower count to surface the more common cookbooks to the top of results. Presumably we'll need to continue to tweak search as we discover use cases from the user base but this is a step in the right direction.
Alright. I lowered the threshold and reverted the change to the spec.