Customization Design (Figma)

Figma design of our customization view and possibilities. To align as a group + get feedback from companies on requirements.

- https://github.com/polarsource/polar/issues/3726
- https://github.com/polarsource/polar/issues/3248
- https://github.com/polarsource/polar/issues/3730
- https://github.com/polarsource/polar/issues/3964