Improve color suggestions (#304)

* Add palettes for each type of color picker.

* Add white canvas background and black element stroke.

* Add white for element background.

src/components/panels/PanelColor.tsx

@@ -3,12 +3,14 @@ import { ColorPicker } from "../ColorPicker";
 
 interface PanelColorProps {
   title: string;
+  colorType: "canvasBackground" | "elementBackground" | "elementStroke";
   colorValue: string | null;
   onColorChange: (value: string) => void;
 }
 
 export const PanelColor: React.FC<PanelColorProps> = ({
   title,
+  colorType,
   onColorChange,
   colorValue
 }) => {
@@ -16,6 +18,7 @@ export const PanelColor: React.FC<PanelColorProps> = ({
     <>
       <h5>{title}</h5>
       <ColorPicker
+        type={colorType}
         color={colorValue}
         onChange={color => onColorChange(color)}
       />