Only split CSV in the client, quote instead of escaping
    
    Splitting on commas is not an idempotent operation:
    'a,b\,c' -> ('a', 'b,c') -> ('a', 'b', 'c')
    
    That means we can't do it when the call is forwarded, so this is only
    done on the CLI. The UI already sends values as a tuple.
    
    Replace escaping in the csv parser with quoting. Quoted strings can have
    embedded commas instead of having to escape them. This prevents the csv
    parser from eating all escape characters.
    
    Also, document Param's csv arguments, and update tests.
    
    https://fedorahosted.org/freeipa/ticket/2417
    https://fedorahosted.org/freeipa/ticket/2227