Reduce boosts on exactish matches

[gaurav]

We currently strongly prefer exactish matches (matching the entire concept name with some part of the query, either as a preferred name or a synonym) -- these are boosted to 100x and more, so they always come above "standard" matches (by token). We also use phrase fields to further boost these fields if they contain query terms close together. We should probably figure out if/how we can simplify this.