feat: add skin preview

[wa0x6e]

Summary

Closes: https://github.com/snapshot-labs/workflow/issues/418
Closes: https://github.com/snapshot-labs/workflow/issues/416

This PR:

• adds a previewer to preview the skin update in realtime
• apply the new skin on space settings change

How to test

Start your dev environment with

VITE_WHITE_LABEL_MAPPING='127.0.0.1;test.wa0x6e.eth' yarn dev

This will put the main app on localhost, and attach the given space on 127.0.0.1

1. Go to your space setting > whitelabel on main site
2. No preview, but you can still update the skins
3. Go to your space settings > whitelabel on your space custom domain
4. Preview is enabled
5. Edit the form (colors, theme and custom logo)
6. The preview should update live
7. Save your settings
8. It should apply your new colors on save

[bonustrack]

Here is how to restyle input color https://codepen.io/leemartin/pen/ExPXRzx

[bonustrack]

Looks like the iframe miss the http(s) so it duplicate the domain

Can you add an icon arrows-expand here that open the preview in a new tab?

Haven't fully tested but there is some issue with the custom logo, we should allow any ratio and not crop the image (like we do in avatars) so it fit with all different logo size, currently it looks like this with Vue.js logo