Tags color and better support for semantic color

[agiguere]

Tags background color in UIKit are grey by default, which looks better than all white

also I believe Tag should have a minimum margin around their border

I need to add semantic colour to my tags (positive, negative, critical), I did not find how so far

https://www.sap.com/design-system/fiori-design-ios/components/tags/?external

thanks

[dyongxu]

@agiguere There is no semantic color support for tags. For the background color issue, we will look into that.