[Java] Added section for converting Avro to Arrow (#235)

* added avro receipe

* updated receipe

* Update java/source/avro.rst

Co-authored-by: david dali susanibar arce <davi.sarces@gmail.com>

* Update java/source/avro.rst

Co-authored-by: David Li <li.davidm96@gmail.com>

* updated per review comments in PR

* fixed extra space issue

Co-authored-by: david dali susanibar arce <davi.sarces@gmail.com>
Co-authored-by: David Li <li.davidm96@gmail.com>
5 files changed