[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.*}

Start by reading the Java ValueVector implementations and the related “remove FieldReader from ValueVector” issue (#411), then reproduce the listed IntVector heap profile with VisualVM. Done should be a measured reduction in the reported ValueVector memory costs, with the affected scenarios and trade-offs documented.

Written by the indexing model from the issue text.