feat(astal4): add the RotatedBin widget

[kotontrion]

Adds a RotatedBin widget, which can rotate its children by a given angle.

Example

      <Astal.RotatedBin angle={90} >
              <label label="Welcome to AGS!"/>
      </Astal.RotatedBin>

Caveats

It currently forces the children to be at their minimum requested size, otherwise the size negotiations get unpredictable.