feat: golden ratio mode

[rommeswi]

(1) Description

On small screens one might not want to use tiling because the active window is too small.
The other windows are often less important or just used to look up information.
The currently active window should therefore take more space and the windows should get resized when switching the active window. Golden ratio mode would allocate screen space according to the golden ratio.

(2) Alternatives I've considered

Manual resizing is of course an alternative but the point of the golden-ratio mode is that the amount of manual resizing is reduced.

(3) Design / Screenshots / Mockups

The inspiration for this feature suggestion is https://github.com/roman/golden-ratio.el for Emacs.