Add exact search specific parameters in kNN query clause.

[harishbhakuni]

Is your feature request related to a problem?
Although exact search with scoring script involves an additional hop of script compilation. it can still be useful for the user if the user requirement involves using different space type for the knn search than the one associated with the index.
To provide the same experience without score scripting, we need to provide additional query parameters in the knn query clause itself.

What solution would you like?
Add exact search specific parameters in kNN query clause.

What alternatives have you considered?
A clear and concise description of any alternative solutions or features you've considered.

Do you have any additional context?
Add any other context or screenshots about the feature request here.

[rchitale7]

I am interested in working on this