[feature] Custom Sticky Notes Icon

**Is your feature request related to a problem? Please describe.**
My browser is full of icons and usually I don't notice when a page I marked long ago has notes. I think this is because the notes icon has light colors and is kinda small.

**Describe the solution you'd like**
Maybe provide 3 or 4 different more striking note's icons or let the user import an image as the icon?