In master, in the 'Theme' tab of the website editor, the button to edit color schemes has a light bulb icon, which doesn't clearly represent what it does. In this commit, we replace it with a palette SVG. Since we-select elements do not have an image option implemented, we also add one for future usage. task-2618494 closes odoo/odoo#75730 Signed-off-by: Jérémy Kersten (jke) <jke@openerp.com>