Deprecate `min_score`

[jpountz]

Quoting documentation: "Note, most times, this does not make much sense, but is provided for advanced use cases".

Besides, it can be implemented easily with a function_score query, which will be as efficient and more flexible since you can put it anywhere in the query tree.

[jpountz]

Actually it is probably not a low hanging fruit because of eg. #14300.

[cbuescher]

@jpountz looks like this is still relevant, but please correct me if I'm wrong
/cc @elastic/es-search-aggs

[jpountz]

It is still relevant indeed, and also #14300 is no longer an issue. I removed the stalled label.

[gmoskovicz]

I am ++ on deprecating min score. For function scores it's fine, but for other queries it's a bad idea as it will work in a way that cuts results but in advance it's not possible to know what score is suitable to be used, and score can vary.