Refactor search + better early return when there are no hits.

[isoos]

• updated offset and limit to be non-nullable and moved range sanitization to the innermost constructor
• extracted best name match into its own method, because it is easily separable from the rest
• extracted predicate filtering in preparation of providing a fast-track to queries without text
• the extracted predicate filtering also allows for an early return check where the offset of query is larger than the available item count
• local benchmark shows no difference in performance