Create a common QueryStatsInfo struct similar to

struct QueryStatsInfo {
    std::unique_ptr<query_stats::Key> key;
    boost::optional<std::size_t> keyHash;
    bool disableForSubqueryExecution = false;
    struct CursorInfo {
        bool willNeverExhaust = false;
    } cursorInfo;
    struct SingleOpInfo {
        bool metricsRequested = false;
    } singleOpInfo;
};

This will be used for both the OpDebug/CurOp QueryStatsInfo and also the ClientCursor and ClusterClientCursor.

This will allow for

• move checks/functions that use queryStatsInfo inside the struct and clean up query stats code overall
• pass QueryStatsInfo to writeQueryStats() and collectQueryStatsMongod/s instead of passing the key itself/flags to divorce std::moving the key from these calls.
• Use disableForSubQueryExecution/willNeverExhaust flags within writeQueryStats() to determine if the query should be collected.

And in general, it would be nice to add comments explaining some of the logic surrounding querystats.