Add new `CsvParser.Feature.ALLOW_COMMENTS` to replace deprecated `JsonParser.Feature.ALLOW_YAML_COMMENTS`

[cowtowncoder]

As of Jackson 2.9 CSV parser allows two methods to enable processing of "hash comments" within cells:

1. CsvSchema has methods to enable this on per-column basis
2. If JsonParser.Feature.ALLOW_YAML_COMMENTS is enabled, default is to enable for all columns (unless explicitly disabled via schema)

Jackson 2.10 deprecates this feature (and adds JSON-specific replacement), so we should add a CSV-specific variant.