refactor: better query debug

[willtj]

@trybeapp/tech FYI in case you were used to going to QueryGrammar and hackily un-commenting the print_r there, like I was 😳 . New way:

\Illuminate\Support\Facades\DB::connection('elasticsearch')->enableQueryLog();
...
\Illuminate\Support\Facades\DB::connection('elasticsearch')-> dumpQueryLogJson();

This will print all logged queries in JSON format that can be posted directly to Elasticsearch for debugging.