Configurable CSV format of SPARQL query output

org.apache.jena.riot.resultset.rw.ResultsWriter outputs a CSV where some fields are double quoted and some are not, based on their content (this is fully compliant with RFC-4180), for example:

entity,language
http://test.org/c1,""
http://test.org/c2,en

Output format configuration makes it more flexible for subsequent processing. For example, parsing of CSVs which contain double quotes all the times simplifies their processing, once  a custom parser needs to be used:

This feature request is to allow the ResultsWriter clients to decide when to use double quotes - e.g. like https://commons.apache.org/proper/commons-csv/apidocs/org/apache/commons/csv/QuoteMode.html

However, given this minimal requirement, an option would be to have a fully OpenCSV compliant implementation of CSV output similarly to CSV parsing (JENA-699) and allow other configurations too (e.g. the quote symbol, as per https://commons.apache.org/proper/commons-csv/apidocs/org/apache/commons/csv/CSVFormat.html).

(The discussion to this issue can be found at JENA-2338)