Add mysql-style LIMIT support to Hive, or improve ROW_NUMBER performance-wise

For any UIs that involve pagination, it is useful to issue queries in the form SELECT ... LIMIT X,Y where X,Y are coordinates inside the result to be paginated (which can be extremely large by itself). At present, ROW_NUMBER can be used to achieve this effect, but optimizations for LIMIT such as TopN in ReduceSink do not apply to ROW_NUMBER. We can add first class support for "skip" to existing limit, or improve ROW_NUMBER for better performance