Support for java.util.{Map, List} and Record container types

Nobody has claimed this yet.

This ticket discusses container datatypes support :-
- java.util.Map instead of StdMap
- java.util.List instead of StdList

The benefits are self evident - A cleaner, familiar and more usable API.
We had already discussed this internally, but I'm not sure why we did not pursue this further at that moment. However, I'm filing this ticket to gauge whether we or anyone upstream would have more interest in something like this.

I tried a prototype for Spark and the results look encouraging. I was able to support [Map](https://github.com/rdsr/t2/blob/master/core/src/main/scala/t2/internal/data/SparkMap.scala) and [List](https://github.com/rdsr/t2/blob/master/core/src/main/scala/t2/internal/data/SparkList.scala) and Struct. For Struct, I rolled my own and provided a Record API. See: https://github.com/rdsr/t2/blob/master/core/src/main/scala/t2/api/traits.scala

Of-course it all depends on a lot of things
- Whether Presto impl. will be able to support this
- Whether making deep backward incompatible API changes are warranted for a more cleaner API.

There are a lot of tradeoffs to be discussed.

Start by reviewing the issue's Spark prototype files, core/src/main/scala/t2/internal/data/SparkMap.scala, SparkList.scala, and core/src/main/scala/t2/api/traits.scala. Then investigate how the framework's Spark, Hive, and Presto implementations handle container types and whether replacing StdMap and StdList with java.util.Map and java.util.List is compatible. Done would require an agreed API design and confirmed engine support.

Written by the indexing model from the issue text.