Support SDF File

[tshauck]

V0 Read SDF file

• [x] single molfile (https://github.com/wheretrue/exon/pull/553)
• [x] single molfile + data (i.e. sd record) (https://github.com/wheretrue/exon/pull/555)
• [x] entire file parser (https://github.com/wheretrue/exon/pull/556)
• [x] SDF to arrow batches (https://github.com/wheretrue/exon/pull/562)
  • [x] schema builder
  • [x] batch reader
  • [x] array builder
• [x] exon integration with table factory

V1

• [ ] Support arbitrary types and fields in Data
• [x] More robust testing of various SDF files
• [x] Add benchmarks
• [ ] Refactor record to lazy record (just bytes) and "hydrated" record.

format docs: https://www.daylight.com/meetings/mug05/Kappler/ctfile.pdf