Add custom properties to uui-tag

[TheRealArtonn]

Extending uui-tag with custom properties in order to style it for the new modern umbraco cloud portal design.

Description

I've added three properties to modify the padding, border-radius and border color of the uui.tag

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Chore (minor updates related to the tooling or maintenance of the repository, does not impact compiled assets)

Motivation and context

We want the ability to adapt the uui-tag better to our own needs and styling.

How to test?

Change properties

Checklist

• If my change requires a change to the documentation, I have updated the documentation in this pull request.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.