Make it possible for JVector users to consume MemorySegmentReader

[jkni]

The JVector jar available through Maven Central packages JVector 11 on the regular class path, with jvector-twenty and jvector-native adding additional classes through multi-release JAR support. This means that users depending on JVector cannot import/use MemorySegmentReader directly. In jvector-examples, we use ReaderSupplierFactory to provide the best reader implementation based on what is available at runtime.

What would be the best way to make MemorySegmentReader available to users building on JVector? Should we provide ReaderSupplierFactory in jvector-base (or something similar, that would provide MemorySegmentReader for nothing, if we think the other implementations aren't production-worthy).

Any thoughts here @mdogan ?