[Java] reduce heap footprint of ValueVectors

In some scenarios, we hold lots of value vectors in memory eg. during join, aggregation. The heap analysis shows that the costs are as follows for a simple IntVector (used VisualVM on mac) :

IntVector : 80 bytes

vector.types.pojo.FieldType : 41 bytes

vector.types.pojo.Field : 40 bytes

IntReaderImpl : 28 bytes

I'll use this Jira to track ways to reduce the heap usage.

**Reporter**: [Pindikura Ravindra](https://issues.apache.org/jira/browse/ARROW-5482) / @pravindra
#### Related issues:
- [[Java] remove FieldReader from ValueVector](https://github.com/apache/arrow-java/issues/411) (is a parent of)
- [[Java] add ValueVector constructors that take a Field object](https://github.com/apache/arrow/issues/21932) (is a parent of)

_{**Note**: *This issue was originally created as [ARROW-5482](https://issues.apache.org/jira/browse/ARROW-5482). Please see the [migration documentation](https://github.com/apache/arrow/issues/14542) for further details.*}

Comece lendo as implementações Java de ValueVector e a issue relacionada “remove FieldReader from ValueVector” (#411); em seguida, reproduza com o VisualVM o perfil de heap de IntVector listado. O trabalho estará concluído quando houver uma redução medida nos custos de memória reportados de ValueVector e os cenários afetados e os trade-offs estiverem documentados.

Escrita pelo modelo de indexação a partir do texto da issue.