add date format configuration

When I set a date value, I see the error message, "Invalid date format. Please enter the date in the format "d/MMM/yy".

We generally use the date format "yy/MM/dd" in Korea.

Also, It is hard to set the value "d/MMM/yy" to Jira because it is contain of global configuration.

I am so happy if you add date format configuration in the portfolio for Jira.