Allow ratings at Query level, in addition to QueryGroup

[mattflax]

We have a client who wishes to just specify queries, without Topic or QueryGroup blocks. However, the current behaviour requires ratings to be set at QueryGroup level, applying to all Query entries underneath - we required ratings to be set on individual Query entries. This PR adds that behaviour, allowing ratings to be specified at both Query and QueryGroup level.

• Ratings at Query level override any set at QueryGroup level (QueryGroup ratings are ignored);
• If a Query has no ratings, it will use ratings from the QueryGroup (as per current behaviour).

I hope this makes sense - let me know if it doesn't.

[agazzarini]

Absolutely @mattflax: as you already got , RRE has born from real use cases...I never met such scenario but I agree with you that can be useful