[Feature Request] Color-picker - Add input slots

[yassilah]

Problem to solve

I have created an eyedropper component to let the user pick a color from a canvas, which works great with the current color-picker component. However, since there currently is no slot inside the color-picker component, i had to patch the current component to include a "prepend-input" and "append-input" slots.

Proposed solution

My solution would be to slightly change the "genInput" method of the VColorPickerEdit component to include "prepend-input" and "append-input" slots. Beyond my personal case, this could also be useful to add a button (e.g. for emitting the input event) or an icon.