Research: Input type color

[gfellerph]

<input> elements of type color provide a user interface element that lets a user specify a color, either by using a visual color picker interface or by entering the color into a text field in #rrggbb hexadecimal format.

As mentioned in #2617, we had <input type="color"> elements in the docs, but they had several issues. It would be good to go back to the drawing board and create a proper design for this component. It's a native browser component, so there are not too many possibilities, but it needs a base style that matches the rest of the Design System without breaking functionality.

### Tasks
- [ ] Create design proposal for color inputs