Select: define the width of select item option

• I have searched the issues of this repository and believe that this is not a duplicate.

What problem does this feature solve?

I has more the 50 items in a multi-select. I think a wide and multi-column or grid drop down panel is better than current single column drop down list.

What does the proposed API look like?

 // the width of select item option (default is as wide as the drop down list )
selectItemWidth: number | string;