DRILL-6544: Allow timestamp / date / time formatting when displaying on Web UI
Added the following options that are setting the format pattens:
web.timestamp.display_format, web.date.display_format, web.time.display_format.
See https://docs.oracle.com/javase/8/docs/api/java/time/format/DateTimeFormatter.html for the details about acceptable values.
Default formatting is used, if the corresponding option has empty string.
